This PDF file contains the front matter associated with SPIE Proceedings Volume 9233, including the Title Page, Copyright Information, Table of Contents, and the Conference Committee listing.

Beach is an important coastal protective barrier and tourism resources. Beach environment monitoring can help beach managers to make feasible decisions. Digital image of video monitoring technology can provide high resolution information of temporal and spatial variation of near shore in real time. The application of Video monitoring technology has been implemented in Qingdao’s Shilaoren beach. The clustering method based on Gaussian mixture model is applied to extract beach enteromorpha changs for the digital images. Analysis results show that, the period of enteromorpha in Qingdao’s Shilaoren beach was mainly from the early July to the mid-August in 2011, and the decline of enteromorpha is mainly associated with the rising temperature in the mid-August. Storm has significant impact on the beach enteromorpha. Tourists’ activity space on the beach will decrease due to the enteromorpha covering on the beach, which affects beach tourism activities. Therefore, it’s necessary to make preventive measures to avoid enteromorpha piling up on the beach, which is of great importance to the bathing beach environment and tourism development.

For identifying digital image authenticity, inherent noise of digital camera as the basis of judgment to calculate cross-correlation coefficient between the test image noise and the camera noise. Then the relevance of noise can be judged through the Generalized Gaussian Model to realize the image authenticity identification. The method has higher detection rate for forged digital images.

Nondestructive optical techniques have been widely used to satisfy engineering applicat ion. 2D digital image correlation (DIC) method has superiority of convenient manipulation and high accuracy in measuring planar displacement. Moreover, fringe pattern profilometry (FPP) method has become a highly developed technique to measure surface profile. Combined with 2D-DIC method, FPP method can be applied to measure three-dimensional displacements conveniently. As a semi-custom integrated circuit, Field-Programmable Gate Array (FPGA) has been popular for its powerful programming performance on controlling experimental instrument. Furthermore, Labview, an efficient graphical programming language which excels in instrument communication, can be used to program FPGA. In this paper, a corrected dynamic FPP method combined with 2D-DIC method has been presented and achieved by Labview programming to measure dynamic deformation. An experimental system including a projector and a camera is used to project fringe patterns and acquire images alternately at a high speed. By the referred method a series of spatial-discrete displacement data in equal intervals of time are obtained. Then a four-dimensional interpolation is adopted to get full-field and continuous-time displacement data. Thus, the planar and out-plane displacements can be simultaneously measured. Experiments were performed and verified the feasibility of proposed method.

Aiming at the block-based fusion methods for multi-focus images, such key problems like finding a suitable block size and overcoming the blocking-artifact often occurs. To address them, we present an intelligent fusion method using particle swarm optimization (PSO) algorithm, which is guided by a structural similarity (SSIM) criterion. In this method, PSO is to fast search for an appropriate block size, while the SSIM is employed as the fitness function in PSO, in order to evaluate the blocking-artifact, thus enabling this method to have a significant improvement in fusion performance. Experimental results show that the proposed method performs better than some classical methods, such as a block-based method similar with ours in fusion rule and multiresolution-based method. Besides, our method preserves more details than others in fused image.

The radiation characteristic of aerial sensor directly affects the quantitative application level of sensor data. In order to study the radiation characteristic, we carried out the radiation characteristic test based on ground tarps laid onto the calibration field of image quality in Anyang, Henan. The airborne sensor was calibrated adopting reflectance-based method. 8 gray-scale tarps and 4 tarps of high reflectance were laid onto the calibration field and they were all with better Lambert radiation characteristic and spectral performance uniformity. Preliminary results show that the bias is larger and the effective dynamic range is smaller and the SNR is lower but the linearity and repeatability are better which can be used to test the response performance of the sensor. Overall, the radiation characteristic tarps laid on the calibration field are suitable for the study of in-flight radiation characteristic of the aerial digital sensor.

The optical measurement technique has been widely applied to detect large surface in product manufacturing for a variety of applications. However, due to some limitations, like the poor image resolution and low measurement speed, this approach is only applicable in the cases with lower requirements in measurement accuracy and speed. To address this difficulty, multiply-cameras based measurement system can be selected, and the selection of multiple cameras also is more economical solution for high image resolution required. However, how to determine the number of cameras and configure these cameras are important issues to avoid the dearth or redundancy of the data acquired. In this paper, a new approach is proposed to solve the layout of the cameras for a structured-light-based measurement system, where a virtual camera model is constructed and used for the determination of cameras’ numbers and locations. The viewports of the virtual cameras are used for the cameras’ arrangements and optimalization layout. The valid of proposed approach has been demonstrated by simulation experiments.

To improve the assembly reliability of Fiber Optic Gyroscope (FOG), a light leakage detection system and method is developed. First, an agile movement control platform is designed to implement the pose control of FOG optical path component in 6 Degrees of Freedom (DOF). Second, an infrared camera is employed to capture the working state images of corresponding fibers in optical path component after the manual assembly of FOG; therefore the entire light transmission process of key sections in light-path can be recorded. Third, an image quality evaluation based region segmentation method is developed for the light leakage images. In contrast to the traditional methods, the image quality metrics, including the region contrast, the edge blur, and the image noise level, are firstly considered to distinguish the image characters of infrared image; then the robust segmentation algorithms, including graph cut and flood fill, are all developed for region segmentation according to the specific image quality. Finally, after the image segmentation of light leakage region, the typical light-leaking type, such as the point defect, the wedge defect, and the surface defect can be identified. By using the image quality based method, the applicability of our proposed system can be improved dramatically. Many experiment results have proved the validity and effectiveness of this method.

The effect and mechanism of smokescreen and stealth jamming on TV seekers are investigated by seeker captive flight jamming test. Based on a comprehensive analysis of large amounts of test results, we have discovered the laws of smokescreen and stealth jamming effect on the performance of TV seekers, such as tracking status, tracking error, measurement of line-of-sight angle and its angular rate. A rational explanation for the laws has also been presented based on the principle of stabilization of seeker optical axis. The results are not only useful for evaluating smokescreen and stealth jamming effect on TV guidance missiles, but also referential for the study of smokescreen and stealth mechanism and the anti-jamming design of imaging seekers.

We present a new method of realizing the spatial-identification image encryption based on digital holography in order to improve the encryption degree and increase encryption freedom. Both the object beam and the reference beam are modulated with random phase respectively. The random phase displayed on the spatial light modulator (SLM) in the reference arm is being refreshed synchronously when the aperture is scanning over the original image. The original image is divided into many subareas by the scanning aperture, and the object beam from each subarea interferes with a reference beam with unique random phase. Therefore, many sub-holograms are captured and each sub-hologram is encrypted with its own sub-key. The spatial position of the aperture becomes additional secret key because it is necessary that each sub-key should match with each encrypted sub-hologram for obtaining a completely decrypted image. This method greatly improves the image encryption degree and guarantees the security of the information. The whole original image is retrieved by superposition of all decrypted subareas. The encryption and decryption are demonstrated by simulations.

The conventional LBP-based feature as represented by the local binary pattern (LBP) histogram still has room for performance improvements. This paper focuses on the dimension reduction of LBP micro-patterns and proposes an improved infrared face recognition method based on LBP histogram representation. To extract the local robust features in infrared face images, LBP is chosen to get the composition of micro-patterns of sub-blocks. Based on statistical test theory, Kruskal-Wallis (KW) feature selection method is proposed to get the LBP patterns which are suitable for infrared face recognition. The experimental results show combination of LBP and KW features selection improves the performance of infrared face recognition, the proposed method outperforms the traditional methods based on LBP histogram, discrete cosine transform(DCT) or principal component analysis(PCA).

An optical key distribution method based on aero-optical effect of boundary layer flow is proposed. The technique exploits the underlying dynamics of the turbulence boundary layer to generate secret key for both communication parties. Corresponding computer simulation and experiments are carried out. The bit error rate of key distribution is 0.05% and 0.22% in the simulation and the experiment, respectively. Further test also shows that the proposed key generation technique is valid to work with optical encryption technique.

Currently fast image mosaic method is less efficient, and most of these methods have low efficiency, poor adaptability, it can not meet the user's requirements. In this paper, a stitching algorithm is presented based on image features. In the method, firstly, the images which are to be spliced using Haar wavelet transform for image de-noising processing; secondly, Haar operator is used to extract image feature points and then uses the template to match the phase correlation method; finally, using a weighted fusion algorithm is proposed for image fusion, the smooth and seamless large completed image will be obtained after the completion of splicing. The experimental results indicate that the effect of the algorithm is better, and has a promotional value.

Distributed machine vision system was applied for the detection on the cable surface defect of the cable-stayed bridge, and access to surface defects including longitudinal cracking, transverse cracking, surface erosion and scarring pit holes and other scars. In order to achieve the automatic classification of surface defects, firstly, part of the texture features, gray features and shape features on the defect image were selected as the target classification feature quantities; then the particle swarm optimization (PSO) was introduced to optimize the punitive coefficient and kernel function parameter of the support vector machine (SVM) model; and finally the objective of defects was identified with the help of the PSOSVM classifier. Recognition experiments were performed on cable surface defects, presenting a recognition rate of 96.25 percent. The results showed that PSO-SVM has high recognition rate for classification of surface defects on bridge cable.

The digital gradient sensing (DGS) method is a full-field optical technique to measure the in-plane stress gradients of transparent materials. Elasto-optic constant is an important material characteristic for the DGS method and is usually not given. On the basis of introducing the working principle of DGS method, a calibration method of elasto-optic constant based on the least-squares method is proposed, and the accuracy of iterative convergence is improved by introducing liner error. A theoretical model of a semi-infinite plane under concentrated normal load on boundary is chosen to verify the feasibility of the proposed method. The full-field experimental data of polymethyl methacrylate specimen is obtained from the digital image correlation method. The experimental results show that the least-squares calibration method can determine the elasto-optic constant of transparent materials effectively.

Based on the period-one nonlinear dynamical state of an optically injected semiconductor laser, an all-optical method for photonic microwave generation is proposed and investigated experimentally. Experimental results show that through jointly adjusting injected optical strength and frequency detuning between the injected light and the solitary laser, a photonic microwave signal with a tunable frequency range of several tens GHz can be acquired. Via by introducing an optical feedback and properly selecting the feedback strength, the linewidth of photonic microwave can be narrowed about two orders of magnitude.

The effect of intermixing in change InGaAs/AlGaAs quantum well structure using impurity-free vacancy disordering (IFVD) technique was investigated. Through the experiment we found that the magnitude of the blue shift changes with the annealing time and the thickness of the dielectric layer. The thicker dielectric layer under the same annealing temperature to withstand the longer, the larger blue shift we got. Cycle-annealing in high temperature for short time to ensure that quantum well were intermixing evidently under the condition of no obvious damage. 46 nm blue shift have been achieved by applying a cycle-annealing at 850°C in 6 minutes for 5 cyclesand the PL peak keep more than 80% of the as-grown sample. Finally, we found that the dielectric film of Si3N4 can suppress intermixing and protect the quality of the samples as the protective film.

At present the optical clock with accuracy and stability achieves to 10^-18 level, which could be the next generation of time and frequency standard. This paper gives an introduction of the progress of researching on the optical lattice clock of Strontium atom in NTSC (National Time Service Center). We realize the (5s5s)¹S₀—(5s5p)¹P₁ cooling (blue MOT) and (5s5s)¹S₀—(5s5p)³P₁ cooling (red MOT) in succession for the optical lattice clock, and loading these cold atoms in a lattice composed by a magic wave-length is studied. By using our narrow line-width diode laser and the fiber femtosecond optical frequency comb, we precisely measure the absolute frequencies of the inter-combination transitions (5s5s)¹S₀—(5s5p)³P₁ of four isotopes of Strontium referenced to an H maser.

We have investigated different growth conditions of AlGaAs and InGaAs quantum wells (QWs) by metal organic chemical vapor deposition (MOCVD) for applications in high-power laser diodes emitting at 980nm. According to different experimental results measured by Photoluminescence (PL), we optimized the growth conditions. Growth temperature, V/III ratio, growth interruption and spacer time have been studied in detail. We have found the optimal growth conditions for laser diodes emitting at 980nm grown by metal organic chemical vapor deposition (MOCVD). As for our experiments, the best suitable growth temperature of AlGaAs and InGaAs QWs was 700°C and 600°C, respectively. The growth procedure of laser diodes should include growth interruption and spacer layers surrounding QWs. V/III ratio was about 130 during the growth of QWs.

We have proposed a new theoretical method for measuring the Brillouin gain of liquids by analyzing the pulse compression ratio that the pump pulse duration to the output Stokes pulse duration. The theoretical model of the pulse compression ratio is presented based on coupled wave equations. The Brillouin gain coefficient can be determined by measuring the pulse compression ratio, the pump intensity and the characteristic length. The application on the measurement of gain coefficient of SBS in some Newtonian liquids will be the subject of further studies.

The parameters of combustion flow field such as temperature, velocity, pressure and mole-fraction are of significant value in engineering application. The laser spectroscopy technology which has the non-contact and non- interference properties has become the most important method and it has more advantages than conventionally contacting measurement. Planar laser induced fluorescence (PLIF/LIF) is provided with high sensibility and resolution. Filtered Rayleigh scattering (FRS) is a good measurement method for complex flow field .Tunable diode laser absorption spectroscopy (TDLAS) is prosperity on development and application. This article introduced the theoretical foundation, technical principle, system structure, merits and shortages. It is helpful for researchers to know about the latest development tendency and do the related research.

The sensitivity of optical fiber ring laser distributed sensing system based on the mechanism of chaotic system’s sensitivity to initial conditions is low. Fiber interferometer distributed sensing system’s sensitivity is high. In this paper, a distributed sensing system with the structure of chaotic fiber ring laser (CFRL) embedding a Sagnac loop interferometer is proposed by combining the property of zero order interference of chaotic light and reciprocity of Sagnac interferometer. It can be used to improve the sensitivity of CFRL sensing system. According to the changes of temporal waveforms, frequency spectrums and autocorrelation functions out of the systems under the same disturbance, the sensitivities are compared between the improved system and the original CFRL system. Experimental results show that the sensitivity of the proposed system is higher than that of the CFRL system. In addition, the response properties of the system under the same amplitude and different frequencies of disturbance signals are measured. The results show that the system can detect the disturbances in the frequency range from 10 kHz to 300 kHz and the responses are flat. The detection abilities to weak signals with different amplitudes are compared. With the rising of disturbance signals amplitudes under the same frequency, the autocorrelation amplitudes of the interference signals increase. In conclusion, the proposed system improves the sensitive to weak disturbance signals with different amplitudes and frequencies. The frequency and amplitude of the disturbance signals can be obtained by the frequency spectrum and autocorrelation function of the waveform of the system.

We demonstrate a 10.5 W passively mode-locked Nd:YVO₄ oscillator end-pumped by 808 nm laser diode. A novel resonator structure with large mode field space is introduced to solve thermal lens effect and semiconductor saturable absorber mirror’s (SESAM) damage, and then we achieve a single-beam-output picosecond pulse laser without inserting any other laser output elements in laser resonator. The repetition rate of mode-locked pulse is 63.4 MHz with 12.9 ps pulse width, corresponding to maximum pulse energy of 166 nJ and peak power of 12.9 kW. In addition, we discover a complete evolution process of pulses from Q-switched mode-locking to continuous wave (CW) mode-locking for the first time.

The two-dimensional (2D) SiO2 photonic crystal (PC) is constructed with the substrate of polyester film. The PC period is 800nm, and the duty cycle is 0.5.The high refractive index coating is deposited on the surface of PC. Rigorous coupled-wave (RCWA) theory is used to analyze 2D PC narrowband reflection spectrum characteristic. A relationship model between reflection peak wavelength and medium refractive index adsorption on surface of 2D PC is established. The conclusion shows that there is a linear relationship between reflection wavelength of the PC and the refractive index of adsorption medium, with the refractive index of adsorption medium in the range of 1.3-1.8. The effects of the refractive index of deposited coating on the sensitivity of the PC biosensor are analyzed. With the increase of the refractive index of the deposited coating, the sensitivity of the sensor is increasing.

Atmospheric turbulence decreases the heterodyne mixing efficiency of the optical heterodyne detection systems. Wavefront tilt correction is often used to improve the optical heterodyne mixing efficiency. But the performance of traditional centroid tracking tilt correction is poor under strong turbulence conditions. In this paper, a tilt correction method which tracking the peak value of laser spot on focal plane is proposed. Simulation results show that, under strong turbulence conditions, the performance of peak value tracking tilt correction is distinctly better than that of traditional centroid tracking tilt correction method, and the phenomenon of large antenna’s performance inferior to small antenna’s performance which may be occurred in centroid tracking tilt correction method can also be avoid in peak value tracking tilt correction method.

A tunable terahertz (THz) filter is reported, which was based on surface plasmonic effects from a subwavelength copper hole array, and the tunability was made possible by a substrate of phase-transition vanadium dioxide (VO₂) film. The phase transition of the VO₂ film was induced by femtosecond laser pulses and the modulation depth of the THz pulse peak by the VO₂ film was measured by THz time-domain spectroscopy to be 80% under optimal fabrication conditions. The change of the conductivity of the substrate film could lead to a shift of the center resonance frequency from 1.33 to 0.92 THz, a relative shift of 30.8%. This tunable THz filter holds great promise for various applications.

A laser signal detecting device is designed for detecting the laser system signal of the shipborne calibration theodolite (hereinafter refers to as theodolite) in the dynamic environment on the sea. The device consists of target board, testing module and data processing module, in which the testing module is fixed in the middle of the target board. A laser beam collimation and expanding lens is designed with ZEMAX, and the theodolite self-stabilization system is adopted to prevent the loss of signal during the test. It is proved that the detection device can meet the detecting requirements with its high detecting precision, easy operation and strong expansibility.

We investigate the thermal denaturation of solid oxytocin using terahertz time domain spectroscopy(THz-TDS). When the peptide is heated up from 25°C to 107°C and cooled down to 25°C again, an irreversible decrease in its THz absorption coefficient and refractive index is observed. The corresponding frequency-dependent permittivity during heating is fitted by the Debye model with single relaxation time. The relaxation times during temperature rising agree very well with Arrhenius equation with the activation energy of 3.12kJ/(K•mol) as an indicator for its thermal denaturation difficulty.

Based on an analogy between the macroscopic phenomena and quantum physics, we study the problem of energy conversion for the sum frequency generation (SFG) process in a linear chirped quasi-phase-matched (QPM) crystal. We show that the process of energy conversion from the signal to the sum frequency field is very similar to the process of Landau-Zener tunneling (LZT) in a two-level system. Therefore, the energy conversion mechanism of SFG process can be explained by the theory of LZT. In addition, we obtain the asymptotic and analytical solution of the sum frequency field by solving the coupled equations with the model of Landau-Zener.

A novel, simple fiber-optic acoustic sensor consisting of a self-mixing effect based laser source and a ring-type interferometer is presented. With weak external optical feedbacks, the acoustic wave signals can be detected by measuring the changes of oscillating frequency of the laser diode, induced by the disturbances of sensing fiber, with the ring-type interferometer. The operation principles of the sensor system are explored in-depth and the experimental researches are carried out. The acoustic wave signals produced by various actions, such as by pencil broken, mental pin free falling and PZT are detected for evaluating the sensing performances of the experimental system. The investigation items include the sensitivity as well as frequency responses of the sensor system. An experiment for the detection of corona discharges is carried out, which occur in a high-voltage environment between two parallel copper electrodes, under different humidity levels. The satisfied experimental results are obtained. These experimental results well prove that our proposed sensing system has very high sensitivity and excellent high frequency responses characteristics in the detections of weak, high-frequency acoustic wave signals.

Supercontinuum generation (SCG) was investigated in tapered tellurite microstructured optical fibers (MOFs) for various taper profiles. We emphasize on the procedure for finding the dispersion profile that achieve the best width of the SC spectra. An enhancement of the SCG is achieved by varying the taper waist diameter along its length in a carefully designed, and an optimal degree of tapering is found to exist for tapers with an axially uniform waist. We also show the XFROG spectrograms of the pulses propagating through different tapered fibers, confirming the optimized taper conditions.

A theory is presented to show the analytic expression of ultra-short pulses existing in a non-instantaneous-response optical fiber with complex parameters. The analytical investigations show that the explicit solitary solutions can be found in form of Jacobi elliptic functions when the imaginary parts of the parameters fulfill a linear relationship. It is found that the single Jacobi elliptic function solutions have two free parameters while hybrid Jacobi elliptic function solutions have only one free parameter.

To restrain the fluctuation of the frequency response curves of the Distributed Feedback (DFB) fiber laser applied in underwater sound detection, based on the principles of Helmholtz resonator, an encapsulation structure is designed, which via protective effects of the trepanning sleeve and the tension added to both ends of the fiber laser. The dynamics is numerically analyzed using the finite element software ANSYS, and the prototype of the new kind of hydrophone based on the structure is manufactured and tested utilizing the vibration jet-method. The results showed that the fluctuation of the frequency response of the DFB fiber laser was restrained effectively within the frequency range of 20 Hz to 800 Hz, and acoustic pressure sensitivity reached to -131dB with the fluctuation less than ±1.5dB.

In this paper, the influences of fiber link and laser source on performances of Radio over Fiber (RoF) including error vector magnitude (EVM), constellation and eye diagram are investigated by simulation using Opti-system12 (trial version). The investigated RoF network is built on IEEE 802.16a WiMAX, with 16 QAM and a Mach-Zehnder modulator for intensity modulation. The mechanism of that the dispersion in fiber link makes the constellation rotate is investigated. The relationship between the rotation angle of the constellation and dispersion is analyzed, where we first put forward a fitting formula to describe this approximate quantitative relation. In the analysis of the influence of the laser source on the network, where the dispersion compensates fiber (DCF) is applied to compensate the rotation in constellation caused by fiber link, the threshold in the relationship curve of the linewidth and EVM is obtained. It is found that if the laser linewidth exceeds this threshold, the EVM will increase rapidly, then, the performance decreases.

A method is presented for generating multiple-channel color-entangled photon pairs simultaneously based on type I quasi-phase-matched spontaneous parametric downconversion pumped in a single periodically poled lithium niobate (PPLN) crystal. It is predicted that one-, and two-channel color-entangled photon pairs can be simultaneously generated just by suitably choosing the PPLN grating period and the pump frequency. We point out that the full width at half maximum (FWHM) of idler and signal light are broadened dramatically due to spontaneous parametric downconversion in case of a pulsed pump.

We demonstrate applications of a novel scheme which is used for measuring refractive index and thickness of thin film by analyzing the relative phase difference and reflected ratio at reflection point of a monolithic folded Fabry-Perot cavity (MFC). The complex refractive index and the thickness are calculated according to the Fresnel formula. Results show that the proposed method has an improvement in accuracy with simple and clear operating process compared with the conventional Ellipsometry.

We investigate the formation of ripple and nanohole induced by femtosecond laser pulses on the surface of silicon. Periodic ripples aligned perpendicular to the direction of laser polarization has been observed. The period of the periodic ripples decreases with the increasing pulse number. Particularly aperiodic ripples with orientation parallel to the laser polarization are formed depend on the number of laser pulses and energy. The nanohole arrays are formed on the overlapped areas of periodic and aperiodic ripples. The interference between the surface scattered or excited wave and the laser itself is proposed to explain the decrease of ripple period.

In order to obtain clear two-dimensional image under the conditions without using heterodyne interferometry by inverse synthetic aperture lidar(ISAL), designed imaging algorithms based on filtered back projection tomography technique, and the target “A” was reconstructed with simulation algorithm by the system in the turntable model. Analyzed the working process of ISAL, and the function of the reconstructed image was given. Detail analysis of the physical meaning of the various parameters in the process of echo data, and its parameters affect the reconstructed image. The image in test area was reconstructed by the one-dimensional distance information with filtered back projection tomography technique. When the measured target rotated, the sum of the echo light intensity at the same distance was constituted by the different position of the measured target. When the total amount collected is large enough, multiple equations can be solved change. Filtered back-projection image of the ideal image is obtained through MATLAB simulation, and analyzed that the angle intervals affected the reconstruction of image. The ratio of the intensity of echo light and loss light affected the reconstruction of image was analyzed. Simulation results show that, when the sampling angle is smaller, the resolution of the reconstructed image of measured target is higher. And the ratio of the intensity of echo light and loss light is greater, the resolution of the reconstructed image of measured target is higher. In conclusion after some data processing, the reconstructed image basically meets be effective identification requirements.

Measurements and investigation were made on the development process and the radiated acoustic wave signal of the two-bubble which is generated by high-power laser reacting with liquid, using the high-speed camera and the high-frequency measurement hydrophone. The result from analysis shows that, the reduced distance between two bubbles and increased laser energy applied on them cause increased interaction between two bubbles resulting in graduallyy prolonged period of two-bubble collapse and gradually increased pressure of cavitated acoustic wave; at the same time, with increasing distance between bubbles, the interacting force between bubbles disappears and both bubbles takes on the characteristics of a single bubble.

Fuzzy control iterative algorithm for beam uniformity enhancement of gas laser through boundary layer flow is presented. The iterative process of the proposed algorithm is controlled by the fuzzy control theory. In each loop, the MSE and the TUI value are evaluated to fuzzily determine which one is relatively greater, leading to different approaches in the iteration. Computer simulation results proved the effectiveness of the proposed method. Gerchberg- Saxton algorithm, profile smoothing algorithm and fuzzy control iterative algorithm are applied to the diffractive optical element design for the correction of laser beam distorted by a Blausius boundary layer. Fuzzy control iterative algorithm leads to better result than Gerchberg-Saxton algorithm and profile smoothing algorithm. Both mean square error and top ununiformity index of the result obtained by fuzzy control iterative algorithm are rather low.

This paper established a model of three-energy-level system from the laser rate equation theory, and then analyzed the molecular dynamic processes and laser mechanism of the optically pumped CH₃OH. According to the experimental parameters, the CO₂ laser is used to pump CH₃OH to emit pulsed THz laser lines. When the 9P(36) line of CO₂ laser pumps CH₃OH, the 118.8 μm line radiation is obtained, and then we analyze the three-energy-level system’s the number of particles and the characteristics of the output waveform, and the influence of the pump light, buffer gas pressure and output coupler reflectivity on laser output power. The results show that this model reveals the generate terahertz optical pump laser process correctly.

The spectrum generated in tapered Photonic Crystal Fiber (PCF) by ultrashort laser pulses is demonstrated via means of numerical simulations of the generalized Nonlinear Schrödinger Equation. Our simulations are able to deliver the spectral evolution of the pulses along the fiber axis at desired propagation distances. Differences of the output spectra and the propagation of laser pulses depending on the different structures of the PCF tapers are investigated. The results show that the variation of the diameter of a tapered PCF along the fiber axis crucially influences the soliton dynamics, the spectral evolution as well as the generation of a supercontinuum (SC). The diameter of a tapered fiber along the fiber axis can be used as a new degree of freedom to tailor the spectrum generated by ultrashort laser pulses.

This paper proposes a novel method of multi-beam laser heterodyne measurement for Young modulus. Based on Doppler effect and heterodyne technology, loaded the information of length variation to the frequency difference of the multi-beam laser heterodyne signal by the frequency modulation of the oscillating mirror, this method can obtain many values of length variation caused by mass variation after the multi-beam laser heterodyne signal demodulation simultaneously. Processing these values by weighted-average, it can obtain length variation accurately, and eventually obtain value of Young modulus of the sample by the calculation. This novel method is used to simulate measurement for Young modulus of wire under different mass by MATLAB, the obtained result shows that the relative measurement error of this method is just 0.3%.

Wide-field optical coherence tomography has a promising application for its high scanning rate and resolution. The principle of a wide-field optical coherence tomography system is described, and 2D images of glass slides are reconstructed using eight-stepped phase-shifting method in the system. Using VC6.0 and OpenGL programming, 3D images are reconstructed based on the Marching Cube algorithm with 2D image sequences. The experimental results show that the depth detection and three-dimensional tomography for translucent materials could be implemented efficiently in the WFOCT system.

We design various silicon nanowire embedded photonic crystal fibers (SN-PCFs) with different core geometries, namely, circular, rectangular and elliptical using finite element method. Further, we study the optical properties such as group velocity dispersion (GVD), third order dispersion (TOD) of x and y-polarized modes and effective nonlinearity for a wavelength range from 0.8 to 1.6 μm. The proposed structure exhibits almost flat GVD (0.8 to 1.2 μm wavelength), zero GVD (≈ 1.31 μm) and small TOD (0.00069 ps³/m) at 1.1 μm wavelength and high nonlinearity (2916 W^-1m^-1) at 0.8 μm wavelength for a 300 nm core diameter of circular core SN-PCF. Besides, we have been able to demonstrate the supercontinuum for the different core geometries at 1.3 μm wavelength with a less input power of 25 W for the input pulse of 20 fs. The numerical simulation results reveal that the proposed circular core SN-PCF could generate the supercontinuum of wider bandwidth (900 nm) compared to that from rest of the geometries. This enhanced bandwidth turns out to be a boon for optical coherence tomography (OCT) system.

In this paper a novel speech recognition methodology based on Hidden Markov Model (HMM) is proposed for embedded Automatic Positioner for Laparoscope (APL), which includes a fixed point ARM processor as the core. The APL system is designed to assist the doctor in laparoscopic surgery, by implementing the specific doctor’s vocal control to the laparoscope. Real-time respond to the voice commands asks for more efficient speech recognition algorithm for the APL. In order to reduce computation cost without significant loss in recognition accuracy, both arithmetic and algorithmic optimizations are applied in the method presented. First, depending on arithmetic optimizations most, a fixed point frontend for speech feature analysis is built according to the ARM processor’s character. Then the fast likelihood computation algorithm is used to reduce computational complexity of the HMM-based recognition algorithm. The experimental results show that, the method shortens the recognition time within 0.5s, while the accuracy higher than 99%, demonstrating its ability to achieve real-time vocal control to the APL.

This paper presents a visual prosthesis image processing system based on Leon3 SoC (System on Chip) platform. The system is built through GRLIB system development platform. It integrates the image preprocessing IP core, image encoder IP core and image data modulation IP core we designed. We transplant the system to the FPGA development board and verify the system functions. The results show that the designed system can achieve the functions of visual prosthesis image processing system effectively.

This paper summarizes the results of a dynamic link attenuation probability study in inter-satellites homodyne BPSK optical communication system. The impacts of the pointing and tracking error on the coherence receiving power are investigated analytically. To evaluate the requirement of optical system aberrations, the link attenuation caused by the aberrations is analyzed. By means of numerical simulation, the probability density function and the cumulative distribution function of bit error probability are calculated by the frequency histogram method.

Based on the dispersive Drude model in metamaterials (MMs), coupled nonlinear Schodinger equations are derived for two co-propagating optical waves with higher-order dispersions and cubic-quintic nonlinearities. And modulation instabilities induced by the cross -phase modulation (XMI) are studied. The impact of 3^rd-, 4^th-order of dispersion and quintic nonlinearity on the gain spectra of XMI is analyzed. It is shown that the 3^rd-order dispersion has no effect on XMI and its gain spectra. With the increment of 4^th-order dispersion, the gain spectra appear in higher frequency region (2nd spectrum region) and gain peaks become smaller.

A novel controllable wavelength-selective coupling photonic crystal fiber (PCF) has been proposed. This coupler allows highly accurate control of the filtering wavelength. The different wavelengths can be selected by controlling the bending radius of the fiber. Coupling characteristics of novel controllable wavelength-selective coupling PCF are evaluated by using a vector finite element method and their application to a multiplexer demultiplexer based on the novel coupler is investigated. When the fiber length is 4741μm, the bending radius of PCF couplers for 1.48/1.55μm, 1.3/1.55μm, 0.98/1.55μm, and 0.85/1.55μm is calculated, respectively and the beam propagation analysis is performed. Different from the traditional wavelength-selective coupling PCF, the dual-core PCF is bent and it can realize the separation of multiple wavelengths.

Fiber grating-pair is one of the efficient methods for gain stabilization of erbium doped fiber amplifier (EDFA) but with a gain-reduction of signals, especially in C-band. In order to overcome it, in this article, we establish a configuration of EDFA based uniform fiber grating-pair and conduct a comprehensive study on gain stabilization by varying the reflectivity, center wavelength and 3dB bandwidth of grating, and by varying the channel number and pump power. The numerical results show that under the optimal parameters of grating the gain stabilization at 1550nm is ±0.044dB with high gain and large dynamic range.

Retroreflective free-space optical communication is a new method of optical communication, it is achieved by using a multiple-quantum-well (MQW) modulator as a passive data transmitter. This work analyzes the polarization propagation of light in the MQW modulator, and the corresponding influence to a retroreflective link. Results show that, on the condition that the intensity and incident angle of the incident light remains to be constant, the polarization and intensity of the transmitted light varies markedly; if the polarization of the incident light is carefully considered for a specific MQW modulator, the retroreflective signals can be improved for a retroreflective free-space optical communication link.

A PPKTP crystal was used to efficient green emission. Spectrum characteristics of FF and SH wave was analyzed, and phase-matching wavelength shift results from thermally-induced poling period shift. A conversion efficiency of 26.1% can be achieved.

It is a challenge to get gain-stabilization and gain-flatness of erbium doped fiber amplifier (EDFA) in C-band, simultaneously. In this article, we establish a gain-clamped EDFA model based uniform fiber grating-pair and optimize the reflectivity of grating by the designed targets. The tradeoff between stabilization and flatness can be obtained when an ideal reflectivity is adopted. The numerical results show that the gain-stabilization is controlled in ±0.1dB and gain-flatness is less than ±1.41dB in the range from 1535nm to 1565nm.

The semiconductor optical amplifier (SOA) is a key device for all optical signal processing based on its nonlinearity, which depends on its group velocity dispersion (GVD). A simple scheme to measure the GVD of the SOA is proposed with some computations from the measured gain spectra based on the relationship between GVD and the optical gain from the Kramers-Kronig relation. The dispersion is relatively flat in the range of 1530 nm~1610 nm, and lightly depends on the input power and the injection current. The peak-gain wavelength and zero-dispersion wavelength red-shift with the input power increasing and blue-shift with the injection current increasing, and the zero-dispersion wavelength is greater than the peak-gain wavelength on the longer wavelength side.

We investigate numerically interactions between two in-phase or out-of-phase Airy beams and nonlinear accelerating beams in Kerr and saturable nonlinear media in one transverse dimension. We discuss different cases in which the beams with different intensities are launched into the medium, but accelerate in opposite (or in the same) directions. Since both the Airy beams and nonlinear accelerating beams possess infinite oscillating tails, we discuss interactions between truncated beams, with finite energies. During interactions we see solitons and soliton pairs generated that are not accelerating. Upon adjusting the interval between the launched beams, their interaction exhibits different properties. If the interval is large relative to the width of the first lobes, the generated soliton pairs just propagate individually and do not interact. However, if the interval is comparable to the widths of the maximum lobes, the pairs strongly interact and display varied behavior. The generated solitons may repel or attract each other. If the overlapping lobes of the two launched beams are out-of-phase, the solitons induced from them repel each other, while if they are in-phase, the solitons attract each other.

In the ultraviolet communication system, ACO-OFDM technology can effectively suppress inter-symbol interference on the system performance, and further improve the transmission rate of the system. However, ACO-OFDM has a high peak to average power ratio (PAPR), and high PAPR not only reduces the power efficiency of the optical modulator, but also bring damage to the human eye or skin. In order to solve the above problem, according to ACO-OFDM signal characteristics, two clipping and filtering algorithms are used, and its performance is simulated, the simulations show that the two algorithms are able to inhibit well the PAPR of ACO-OFDM system.

A bandwidth-enhanced chaos synchronization communication system is proposed and its communication performance is investigated numerically. The results show that, using a bandwidth-enhanced chaotic signal from a driving vertical cavity surface-emitting laser (D-VCSEL) to drive two mutually coupled VCSELs (MC-VCSELs), the high-quality isochronal chaos synchronization with over 30GHz bandwidth between two corresponding LP modes in the two MCVCSELs can be obtained. Taking two LP modes as two different communication channels and adopting chaos masking (CMS) encryption scheme, this system can realize the bidirectional dual-channel high-speed chaos communication at 10Gbits/s transmission rate. Moreover, the parameters mismatches tolerance of this communication system and the influence of message transmission rate on the communication performance also are discussed.

A compact dual-structure waveguide triplexer which consists of two waveguide gratings with different period and fill factor is presented. It not only achieves efficient coupling between single mode fiber and a silicon-on-insulator optical waveguide, but also realizes effectively splitting, especially, for three different wavelengths, i.e. 1.31μm, 1.49μm and 1.55μm. By appropriate choice of waveguide/grating parameters including thicknesses, periods, height, and fill factor, to optimize the mode matching, and improve coupling efficiency and decrease the value of crosstalk, the coupling efficiency for 1.55μm wavelength can reach about 70% for TE polarization light over the 40 nm wavelength bandwidth. The crosstalk is about -12dB. Simultaneously, for 1.31μm and 1.49μm, the coupling efficiency is 58% and 40%, respectively. Moreover, the crosstalk of the left and the right branch of waveguide is -10dB and -14dB, respectively.

White light-emitting diodes are gradually dominating the illumination markets that new design challenges arise for this emerging source. Based on the white LEDs, an efficient optimization method is presented for integrated reflective optics. During the design process, initial structure of reflective optics is numerically calculated. For further optimization, initial parameters are adjusted by section-modeling method to determine optimal starting point. To complete the design, subsequent spline-modeling method is applied. Design example show that the designed reflective optics for LED illumination could offer both high performance and low space occupancy rate. Comparing to the numerical method, the method offers a 15% uniformity improvement and 6-times rise of processing efficiency. It is believed that the effective optimization method will has practical applications in other integrated optics.

The enhanced Raman spectroscopy (SERS) substrates were obtained using self-assembly Ag nanoparticles on the surface of glass modified with 3-aminopropyltrimethoxysilane (APTES), where the Ag nanoparticles were synthesized by aqueous reduction of AgNO3 with trisodium citrate. The surface morphology of thin films with assembled silver nanoparticles was studied with UV-Vis spectroscopy and SEM. With the probe molecule of Rhodamine 6G, the Raman spectra on self-assembled Ag nanoparticle substrates were detected, which showed a great increase of Raman signals for Rh6. The surface plasmon resonance (SPR) of the assembled silver nanoparticles depended on the distance between the particles, the adsorption of molecules, and the assembly structure. Experimental results indicated that he intensities of the Raman peaks increased concomitantly with the increase in the concentration of Rh 6G. The detection limit of the assembled Ag nanostructures was 10⁻⁸M. In this paper, the results further confirmed that the nanoparticles assembled method was an effective method for the increase the signal of SERS.

A general numerical solution for the dynamics of microring resonator modulators is proposed by using signal flow graphs. Fields are calculated according to the signal flow graphs. The solution is suitable for many kinds of microring resonator modulators. Coupling modulation resonators with symmetric Mach-Zehnder Interferometer coupling regions are studied by the method. Results show that the method provides theoretical rigor and wide applicability to microring resonator devices.

Along with the continuous renewal of the light source, LED light source could have been used in the lights of airfield already. LED light source in the application will be more energy efficient. This paper designs the optical structure of the taxiway centerline light,which is used on the bend. Osram LT CPDP - KZ - 4 green LED has been chosen to be the light source.Optical components used in the structure, such as the prism, the lens, the scattering pieces, is designed on the basis of the optical design principles. The optical design principle include the edge-ray etendue conservation, conservation of energy and so on. Then, the structure is drawn and simulated. Completing these steps combines with software, such as ProE, Matlab and TracePro. To test the optical structure with Yuanfang GO-2000 distribution photometer. The test results meet the standards of the civil aviation administration’s requirements. In order to further reduce energy consumption, and optimize the components on the premise of meeting the requirements of national standards. The paper reduces the input current from 900mA to 400mA by optimizing the components. The method of optimizing is combining the prism with scattering pieces and optimizing the lens surface. The optical structure of the taxiway centerline lights used on the bend after improving is more efficient and meet the requirements of national standards including chromaticity and light intensity.

Waveguide photodetectors (WGPDs) are considered a leading candidate to overcome the bandwidth-quantum efficiency trade-off as the flow of the photon and carrier fluxes are perpendicular to each other enabling high date rate applications. Mushroom-WGPD was proposed to overcome the trade-off between the capacitance of the photodetector and the contact resistance. In this paper, an extended calibrated circuit model for mushroom-WGPD, including the effect of the biasing of the photodetector, is presented so resulting in the feasibility of a complete circuit simulation of the entire photoreceiver circuit. The effects of the biasing over the performance of Mushroom-WGPDs have been explored for different loads and different dimensions of the device. Based on the studies of different parameters for design and materials, optimization has been performed for the mushroom-WGPD. With this optimization, the optimal values of the thickness of the absorption layer to produce the highest bandwidth of the photodetector are obtained for different biasing values. These optimizations are performed for different areas of the photodetector and also for different load resistors, and they result in a significant improvement in the performance of the mushroom-WGPDs.

Solar cells’ photoelectric properties calibration, i.e., current-voltage (I-V) characteristics is critical for both fundamental research and photovoltaic production line. This paper will present calibration of solar cells’ I-V characteristics by a substitution method under simulate light source. Considering the calibration uncertainty and measurement accuracy, reliable measurement procedures developed in NIM with uncertainty analysis are also demonstrated. By controlling the influencing factors, relative expended combined uncertainty (U_rel) of 2.1% (I_sc), 1.0% (V_oc) and 3.1% (P_max) was concluded here, with a coverage factor k = 2. The measurement system meets all requirements of IEC 60904-1 and IEC 60904-9, and it has been applied to amounts of solar cells’ I-V curves calibration for research institutes as well as industrial plants, which solved the problem of domestic metrology technology shortage in photovoltaic field.

We present an improved phase generated carrier (PGC) demodulation method named PGC differential-self-multiplying-integrate (PGC-DSMI) algorithm in this paper. The performances of the new demodulation method are ameliorated via the elimination of the coefficients in the result of conventional PGC-differential-and-cross-multiplying (PGC-DCM) method. The advantages of the improved method are demonstrated theoretically and proved in the simulation. The results show that PGC-DSMI has a better linearity than PGC-DCM.

This paper proposes a thin-film stress measurement system. By applying a constant velocity to the projection grating along the grating plane, a series of sampling points of the sinusoidal wave can be recorded using a CCD camera. The phase distribution of the optimized heterodyne moiré signal can be extracted by the least-squares sine fitting algorithm and then the surface profile of the tested flexible substrate can subsequently be acquired. Using polynomial fitting method to depict the cross-section curve of the substrate, estimating the resultant curvature radii of the uncoated and coated substrates, and substituting these two radii into the corrected Stoney formula, the thin-film stress of the flexible substrate can consequently be obtained. This method features high stability and high resolution due to the introduction of the projection moiré and heterodyne interferometry.

Based on sublayer division and backward recursion algorithm, the nonlinear reflection spectra at normal and oblique incidence for one-dimensional photonic crystal (1DPC) with one Kerr nonlinear defect are investigated. When incident intensity is higher than the incident intensity threshold, the defect mode appears inclined curved multiple-valued features at certain wavelengths. Compared with the circumstances of normal incidence, the full width at half maximum (FWHM) of the TE wave becomes smaller and that of the TM wave becomes greater. The change of FWHM also arouses the change of the incident intensity threshold. For the 1DPC with third-order nonlinear coefficient χ⁽³⁾>0, the defect mode position would be determined by the incident angle and incident intensity together and the minimal separation angle of TE wave and TM wave is decreased with increasing the incident intensity. While for the 1DPC with third-order nonlinear coefficient χ⁽³⁾<0, the defect mode moves towards shortwave direction when increasing incident intensity or incident angle. Besides, the minimal separation angle of TE wave and TM wave is increased with increasing the incident intensity. This research provides a valuable reference to the design and application of polarization filters, optical sensors, tunable filters and so on.

A Q-switched Er-doped fiber laser is demonstrated using graphene as saturable absorber (SA). The graphene SA is fabricated to the fiber end using optically driven deposition method. As we increase the pump power from 128 mW to 380 mW, the pulse repetition rate of the Q-switched fiber laser changed from 23 to 67 KHz and the pulse width varies from 5.2 to 0.9μs. A repetition rate of 67 KHz is obtained at the maximum pump power of 380 mW, with pulse width and pulse energy of 0.9μs and 179 nJ, respectively.

A light intensity distribution generated by an electro-optic tunable multiphase array based on the Talbot effect under lower external electric field was demonstrated. This 2-D distribution is mapped as a 2D hexagonal tunable phase array based on the periodically poled MgO-doped LiNbO₃ crystal (PPMgLN). Applying a lower external electric field through the Indium Tin Oxide (ITO) electrodes coated on the +z and –z surfaces of PPMgLN crystal, a tunable PTAI was fabricated. The self-imaging phenomenon of Talbot effect in the Fresnel field for this phase array coherently illuminated is theoretically analyzed according to Fresnel diffraction theory. The experimental and theoretical results show that the self-images visibility depends on array duty cycle and external electric field for a fixed diffraction distance. The optimal self-images visibility can be obtained at array duty cycle of 52%, phase difference of 0.75π for diffraction position of 0.33 times Talbot distance. Moreover, a preferable self-image pattern can be observed under an unprecedented lowest external voltage of 0.461kV correspond to phase difference of 0.35π，which is beneficial to optical integration and micro optical devices.

A fiber Bragg grating (FBG) sensor for simultaneous measurement of temperature and force is proposed and demonstrated. Where a part of uniform FBG (about one half length of an FBG) is attached on the polymer open loop, the FBG is divided into two parts which has an equal length. So the two parts can be regarded as two FBGs. Because of the difference of the Young’s modulus and the thermal expansion coefficients for two parts of the FBG, the two Bragg reflection wavelengths are shift when the temperature and force are applied on the sensor. Simultaneous measurement of temperature and force is demonstrated experimentally. The experimental results show that the linear response to temperature and force are achieved. The value of applied temperature and force can be obtained from the two Bragg wavelength shift via the coefficient matrix. This study provides a simple and economical method to measure temperature and force simultaneously.

To meet the demands of safe and comfortable driving, we present a new design of a highly energy-efficient Adaptive Front-lighting System (AFS) that can automatically adjust the shape, range, and light distribution of the illumination. The AFS system consists of a lamp, a reflector, light pipes, a Digital Micromirror Device (DMD), a condenser, and a lens. Our simulations show that this system can achieve different beams, such as basic passing beams, town beams, motorway beams, and corner lighting. By using the second light pipe to collect light, the illumination efficiency is increased by 10 points, accordingly reducing the generated heat of the lighting system.

Optical systems with long effective focal length and large-aperture will play more important roles in space remote sensor in the future. Coaxis optical systems have been widely adopted due to its advantages including good symmetrical characteristics, compact structure, satisfying volume and rotary inertia. But the distortion of the coaxis three-mirror-anastigmat system is often larger than one percent of the image height and past correction is hard, which is unfavourable especially for surveying and mapping camera. Based on the design ideas and aberration theoretical analysis of Coaxis reflective optics, four-mirror systems with long focal length is presented in this paper, which can achieve high image quality and ultra-low distortion .The forth reflective mirror is set near the exit pupil to correct the aberration related to the pupil, and the processing difficulty of the primary mirror is also lowered. Example of the optical design and image quality forecasting is also given at the end of the paper.

A design scheme of compact polarization rotator (PR) for silicon-based slot waveguides is proposed, where the slot including the upper claddings is filled with liquid crystals (LCs). With this design, the transverse field components of eigenmodes supported by the slot waveguides have almost identical amplitudes due to the anisotropic features of the LCs, leading to a high modal hybridness, which plays a pivotal role in designing an efficient PR. As a consequence, the input TE (TM) mode can be converted efficiently to the TM (TE) mode at the output port within a short length. The numerical results show that a PR of 11.3m in length at the operating wavelength of 1.55m is achieved with the extinction ratio and insertion loss of 12.6 (11.5) dB and 0.22 (0.30) dB, for TE-to-TM (TM-to-TE) conversion, respectively. Moreover, field evolution along the propagation distance through the PR is also demonstrated.

The chlorophyll-a and turbidity sensor based on the principles of fluorescence induction and scattering-light detection is designed. Using fluorescence induction technology, scattering-light detection technology and weak signal detection technology, chlorophyll-a concentration measurement and turbidity measurement in seawater are integrated in a set of testing equipment to implement software and hardware reuse and improve the integration of the device, which has the features of small size and easy operation. The comparative experiments and repetitive experiments are completed with ALEC ACLW-CAR chlorophyll / turbidity sensor. Experiment results show that chlorophyll-a concentration, turbidity and the system output values have good linear relationships, and the fitting coefficients are 0.999. Repeatability standard deviations of chlorophyll-a detection and turbidity detection are better than 0.08 μg/L and 0.04 FTU, respectively, and the accuracy of the device within ± 2%. Chlorophyll-a and turbidity in-situ monitoring in seawater can be achieved using this testing equipment.

Spectral hole characteristics of Tm³⁺: YAG under cryogenic temperature was studied. Higher temperature broadens hole width exponentially while leads to hole depth decay, and spectral hole disappeared above 11.2 K. Measurement confirms the prediction.

In this paper, a multi-port THz Fourier transform spectrometer is designed to measure Terahertz spectrum. Multi-port optical design make spectrometer more flexible used on pot light source and collimated light source directly, which eliminating the need of external conversion optical path for different light source, and also allows using a variety of external detectors flexibly, extending the spectrometer’s measured range. The Fourier transform spectrometer is described.

The existence of phase error influences the imaging performance of optical synthetic aperture system and limits the resolution of the imaging system. The relationship between point spread function of binocular system and piston error is analyzed and the conclusion that the relation between point spread function and piston error is irrational with coordinates along the perpendicular bisector of baseline has been deduced and proved. Therefore the effect of position accuracy to error detection is avoided. The distribution characteristic of point spread function on baseline determines the range of piston error and by which a unique value of piston error is obtained. Finally, the piston error detection method of binocular system is extended to the common optical synthetic aperture system. Simulation experiment demonstrates that this method can conquer effect of various noises and the detection accuracy is better than 0.004 times of wavelength.

The generalized theory of double-mode electrostatic dispersing prism for time-domain compressing electron pulse is presented. The fundamental difference between the two modes of o mode and e mode lies in the dispersive dependence of electron’s time of flight on its initial kinetic energy at prism entrance: the electrons with higher initial axial energy definitely have longer time of flight for o mode, while not the case for e mode, which results from the electron pulse’s Ushaped motion in the prism. The dispersive dependence of time of flight constitutes the mechanism of electron pulse compression for each mode. An example is given to demonstrate the issue of parameter choosing for the prism and to verify its tunable performance of electron pulse compression.

NaYF₄ nanoparticles are doped into PCDTBT:PCBM blend as a dual function additive to improve light absorption of inverted polymer solar cells. The dependence of device performance on NaYF₄ in the blend film is investigated. The results show that the short-circuit current density is apparently enhanced by doping NaYF₄ into the active layer while maintaining the open-circuit voltage and fill factor, leading to an increase in power conversion efficiency. NaYF₄ maybe play two kinds of role for light absorption enhancement. Up-conversion (UC) emission from Y³⁺ is observed. The scattering effect of NaYF₄ nanoparticles (NPs) enhances the light absorption in visible region. The performance of polymer solar cell doped with NaYF₄ is compared with that of undoped. The concept of integrating nanoparticles into active layer suggests a promising and practical pathway for improving absorption of polymer solar cells.

We investigate the light propagation characteristics that depend on strong dispersion response in two-ring resonant structure. Strong dispersion response brings obvious effective phase shift change in resonant arm of Mach-Zehnder interferometer. We propose that two-ring coupled Mach-Zehnder interferometer exhibits sharp asymmetric Fano line shape. It mainly decided by the combined action of a π/2 phase bias in reference arm and effective phase shift in resonant arm. It can greatly enhance the sensitivity of sensor. It allows for measuring effective refractive index change down to 10^-9 refractive index units.

In this work, transparent amorphous InGaZnO (a-IGZO) thin films have been deposited on quartz glass substrates using RF magnetron sputtering at room temperature at the O₂ flow rate from 0 to 4 sccm. Electrical transport properties and optical transmittance of the a-IGZO films strongly depend on O₂/Ar flow rate ratio. Electrical conductivity of the a- IGZO films dramatically decreases from semiconducting to semi-insulating with increasing the O₂ flow rate above 1 sccm. Optical transmittance of the a-IGZO films, however, has been improved up to 85% by increasing O₂ flow rate. Amorphous IGZO-based thin film transistors have been developed on indium-tin-oxide glass substrates with the phosphorus doped nanogranular SiO₂ film of ~800 nm deposited by plasma-enhanced chemical vapor deposition at room temperature as the gate dielectric layer. The accumulation of protons at the IGZO/SiO₂ interface induces a large electricdouble- layer capacitance. Enhancement-mode IGZO/SiO₂/ITO TFT devices with field effect mobility of 10.5 cm²/Vs and low threshold voltage of 0.7 V have been achieved. Furthermore, a-IGZO TFT devices exhibit subthreshold swing of 70 mV/dec and I_on/off of 1.5x10⁶. Optical transmission spectra show that the a-IGZO thin film transistors arrays on glass substrates is highly transparent with optical transmittance above 80%.

A plasmonic device for gas sensor is investigated for refractive index detection using surface plasmon resonance (SPR). The sensor device consists of nano-cavity antennas formed by metallic rectangular nanostrip array over a metal film, which monitors the changes of the refractive index by measuring the spectral shift of the resonance angle dip. The average detection sensitivity of the gas sensor is about 136 ° / RIU (refractive index units) for SPR excitation at 1550 nm telecommunication wavelength.

The polarization-maintaining photonic crystal fiber’s phase sensitivity dependence on temperature was analysis. The relationship between temperature and phase of normal polarization-maintaining fiber and polarization-maintaining photonic crystal fiber was numerical analyzed and experimental tested. Furthermore, the Shupe effects in fiber optical gyroscopes with the two fibers were studied. The contrast results showed that the phase sensitivity dependence on temperature of the polarization-maintaining photonic crystal fiber is quantitatively comparable to normal panda fiber. And the Shupe errors of the gyroscopes with the two different fibers were at the same level.

We present a method to accurately measure the polarization parameters of high birefringence polarization-maintaining (PM) fibers using a distributed polarization analyzer. By measuring a equidistant periodic cross-talks peaks along the PM fiber induced by the pressure of an thin metal cylinder between the spool and the wound fiber, the group birefringence perturbations along the length of PM fiber can be accurately obtained. By finding the widths of measured cross-talk envelopes at known distances along the PM fiber, the birefringence dispersion variable of fiber can be obtained. By analyzing cross-talk peaks purposely induced at both ends of the PM fiber, the temperature coefficient of group birefringence can be accurately obtained.

In order to solve the problem of high voltage driving of nano-diamond coating field emission display, a driving circuit with gray-scale modulation and high-low voltage conversion is designed. Hardware circuits are based on assembled data driving chips of HV632PG and HV5308, which form the framework of gray-scale modulation and scanning display circuit; as well as, the framework of before and after low-level high-low voltage isolated and converted circuit is assembled based on half-bridge driving chip IR2235. Test the whole characteristics of software and hardware circuits, the dynamic display of simple image and character is realized on the screen of LED, which lays a certain foundation of theory and experiment for developing the application of nano-diamond coating FED of large screen.