Optical meta-devices are composed of the collection of artificial subwavelength nanostructures. Phase, polarization, or amplitude of the incident electromagnetic waves can be manipulated by the specifically designed meta-devices. The demands of the new generation of photonics currently extend from classical to quantum optics. We report our progress in the design, fabrication, and application of the novel optical meta-devices from classical to quantum optics. We show a novel achromatic meta-lens array light field optical system for applications in imaging and sensing. We integrate a meta-lens array with a thin slice BBO nonlinear crystal to form a high-dimensional quantum entanglement optical chip. Results of the excellent mutual entanglement fidelity in 2-dimensional, 3-dimensional, and 4-dimensional experiments have successfully demonstrated the novel function of our high-dimensional optical quantum chip.

The increasing demands in industry, for example for products in the consumer electronics sector or for assistance systems in cars, and the continuous development in semiconductor are leading to significant miniaturization in electronic components. These requirements are inevitably also transferred to ultra-precise manufacturing and thus ask for monitored production steps. In the context of Industry 4.0 and other developments in the context of modern production sensors to supervise production steps are crucial. An essential component here is non-destructive testing (NDT) and specifically optical metrology. Precitec Optronik is developing since decades intelligent sensor systems based on chromatic confocal or interferometric measurement principle. To meet the need of additional, even complex and time sensitive measurement tasks, Precitec Optronik has developed the Flying Spot Sensor. The active measuring head was specially developed for in-line use and ideally complements the spectral interferometric sensor to form a smart inspection system. The light from the sensor is coupled into the measuring head via a light guide and deflected by a mirror system, a so-called galvanometer scanner. Finally, the light passes through a telecentric lens, which serves as a focusing module on the outward path and as a measuring aperture for the reflected light. Due to the movable mirror system, the measuring light beam can be deflected at different angles and thus the measuring spot can be freely positioned within the field of view of the lens. Long paths of linear axes are replaced by short rotary movements, resulting in an extreme reduction of the measuring, or scanning time. By using specialize focusing modules, the Flying Spot Scanner can be adapted to different application scenarios. These optics are characterized by a low curvature of the focal plane, very small telecentric errors and a very large depth of field. The measurement system can also be used in two operating modes, a thickness mode, or a distance mode. The two operating modes can be selected at will via the digital interface, which means that the switching process can be easily integrated into an automatic measuring sequence.

Phenanthraquinone-doped polymethylmethacrylate (PQ/PMMA) photopolymer is a promising material for holographic data storage, according to the negligible shrinkage, polarization sensitivity, and easy preparation. In this paper, we investigated the effect of thermal polymerization temperature and time of PQ/PMMA on the collinear holographic data storage system. By designing the baking temperatures 50℃ and 60℃ and baking times 4-20 hours each 2 hours during thermal polymerization. The information page storage and representation results show that under the baking temperature of 50℃ when the baking times were less than 8 hours, the material could not record the data page, and the bit error rate (BER) of the reconstructed data page was increased with the baking time extension. The material baked for 10 hours recorded data with the best results and reconstructed data pages with a minimum BER of 1.5%, when the baking time is 20 hours, the BER of the reconstructed data page was increased by about 12% compared to the baking time of 10 hours. When the baking temperature is 60℃, the data page BER was also increased with the baking time extension except for a very short baking time within 2.5 hours. We analyze the molecular weight of these materials that can be changed by controlling the baking temperature and time of thermal polymerization properly so that grating generation and readout efficiency can be changed. We believe the analysis is useful for the application of PQ/PMMA on collinear holographic data storage.

The null reconstruction can be used to realize multi-channel recording, thereby improves the storage capacity. In this work, phenanthrenequinone-doped poly(methyl methacrylate) photopolymer (PQ/PMMA) that is sensitive to the polarized wave, is used as the recording medium. To better reach the null reconstruction, we need to control exposure time and intensity in the recording stage. By adopting the suitable experimental parameters, the crosstalk between the two holograms is negligible. The analysis of the experimental results shows that the ratio of optical powers of the signal wave to that of reference wave is 1:8-1:10, the exposure time is about 12 minutes, and the optimal signal-to-noise ratio can reach 21:1.

Photopolymerization assisted by up conversion nanoparticles (UCNPs) are reported to have promising potential in the biological field due to the unique fluorescent features of UCNPs. Here, we demonstrate a novel method in the fabrication of three-dimensional (3D) features at low power level with unique photo-luminescence property through the incorporation of UCNPs under a far-field direct laser writing (DLW) configuration. Equipped with long lifetime of excited energy levels, UCNPs were employed to function as the excitation light source for inducing controlled reversible deactivation radical polymerization through activating polymerization photo reagents via resonance energy transfer in the localized area surrounding the UCNPs, hence generating polymerized micro-scale features upon an incident near-infrared laser beam. UCNPs with unique emission qualities were custom-synthesized and dispersed in a monomer-based mixture containing polymerization photo-reagents to formulate a photo-sensitive nanocomposite. A thin film sample based off the nanocomposite was then placed under a DLW scheme for the fabrication of 3D micro-structures at low power level (100sW/cm2 for the writing laser beam intensity). Able to fabricate 3D micro-structures at very low power level with unique photo-luminescent properties compared to the traditional two-photon polymerization technique, this new method of laser fabrication method assisted by UCNPs has significant potential applications in research domains such as 3D low-power nanoscale optical memory, high-resolution imaging/display, functional micro-photonics devices and 3D micro-prototyping.

Heat-assisted magnetic recording (HAMR) is a promising technology to increase the recording density of hard disk drives to more than 10 Tb/inch2. In HAMR, a near-field transducer (NFT) is necessary to form a light spot with the order of 10 nm to heat the recording medium locally to reduce its coercivity during recording. The authors’ group has proposed a device for HAMR, in which a metal nano-antenna acting as an NFT is attached to a semiconductor ring resonator acting as a light source. Because the characteristics of near-field light are influenced by the material and structure of nano-antenna, we investigated a metal-dielectric hybrid nano-antenna in this study. Especially, a core-shell-type nano-antenna, in which a dielectric sphere as a core was embedded in a gold tip as a shell, was taken as an example, and how the core refractive index and core radius influence the energy density and spot size of near-field light was numerically simulated. The tip radius of nano-antenna was 25 nm. As a result, when the core radius was 20 nm, maximum energy density of about 25 times and minimum spot size of about 91% compared with conventional gold-only nano-antenna were obtained at the core refractive index of 4.4 and 4.8, respectively. As the core refractive index became higher, the optimum core radius became smaller. Moreover, the behavior of energy density could be understood by one-sphere model and that of spot size could be understood by two-sphere model, both of which are determined by the localized surface plasmons.

Augmented Reality (AR) and Head-up Display (HUD) applications are nowadays taking advantage of the pupil replication that it is possible to achieve with waveguide combiner to increase the eye box without sacrificing the field of view. However, most of the waveguide combiners are limited with flat geometry to avoid unwanted optical power. Flat waveguide ensures that no aberration is imparted to the image when the light propagates inside the medium. Yet, the aesthetic appeal of a flat combiner is not ideal since neither wearing glasses nor vehicle’s windshield is flat. Here we propose a 1-D curved waveguide combiner that take the advantage of holographic optical elements (HOE) to minimize the aberration for 2-D pupil replication. Both ray tracing model and experimental demonstrator will be discussed.

Computer generated holograms (CGHs) used for AR/VR displays typically have poor image quality compared to their numerical reconstructions. The primary cause of these discrepancies can be attributed to over idealized wave propagation used for CGH generation. This problem is often exacerbated when the image is projected through a more complex optical system like a holographic waveguide combiner or using the Texas Instruments phase light modulator (PLM) that has nonlinear phase levels. Direct camera feedback during hologram optimization has been shown to significantly improve image quality for CGHs projected in free space. Here we demonstrate the use of camera feedback optimization for improving image quality of CGHs projected through holographic waveguide combiners and using the TI PLM as phase SLM. Machine learning can be applied to create adjust the numerical propagation method to closer match physical propagation through the system without the need for camera feedback after training. This method corrects for various optical aberrations, beam profile, and phase nonlinearities in the display. Further image improvement is made by leveraging high speed MEMS based PLM for time multiplexing CGHs to reduce speckle. Application of these techniques for different waveguide geometries (i.e. planar and curved) will be discussed.

The state-of-the-art position of cameras in forward-facing Advanced Driver Assistance Systems (ADAS) is behind the windshield, integrated within the rearview mirror holder. In this position, the quality of the windshield as an optical element directly impacts the quality of the camera image. With increasing camera resolution and narrow field of view optics required for large object detection distances, the optical impact of the windshield becomes increasingly important. We suggest a method based on computer graphics for evaluating the optical performance of windshields in front of ADAS cameras. Using a ray tracing framework, we produce quantitative simulations of the light transport through the windshield. To represent the geometry of the windshield, we fit ellipsoid models to measurements of its inner and outer surfaces produced using a chromatic white light sensor in a coordinate measuring machine. The ellipsoid fits enable accurate ray intersections with the windshield even for cameras positioned close to the windshield surface. Additionally, we investigate the windshield microgeometry using optical profilometry and find that the microstructure is smaller than 200 nm. Thus, the microgeometry can only cause a very slight diffractive blur, and we consider the ellipsoidal macrogeometry sufficient for evaluating the light transport. In simulation experiments, we evaluate the impact of the windshield on a forward-facing ADAS camera by computing the modulation transfer function degradation of the camera image. In our experiments, we vary camera aperture and resolution as well as distance and angle of the windshield to the camera. To validate our results, we reconstruct the angle variation experiment in the lab.

We inspired and learned from nature to develop the meta-lens array for intelligent imaging and sensing. The design, fabrication, and applications of the intelligent meta-lens array are reported in this talk. We developed the meta-lens array based light field imaging system for digital focusing, full-color imaging, depth sensing for static and dynamic objects, and 1D to 3D edge detection. This research shows the importance of optical meta-devices for next-generation optical imaging and sensing. We believe this opens up an avenue for future applications of optical devices in micro-robotic vision, unmanned-vehicle sensing, virtual and augmented reality, drones, and miniature personal-security systems.

Machine vision system has great significance for the automatic inspection to enhance unclear defects. For the improvement of the recognition accuracy in the automation inspection, in addition to development of image-processing technology, the optical technology is also required to emphasize the contrast of defects difficult to find in a camera. Here, we develop both the optical-engineering and image-processing technology with high throughput to enhance defects in transparent material, using the phase-shift illumination method with striped structured illumination. We succeeded in the enhancement of shape defects difficult to visualize in a bright-field observation with our approach to construct the composite image from a few pictures. Our challenge of development has been the discrimination of actual defects from dark fringes due to the artificial and periodic structures which is prepared for the improvement of optical performance or design, such as embossing film or micro-lens array. To overcome this issue, we suggested that artificial textures with the gentler slope should be more insensitive than actual defects by providing the illumination pattern with finite-width dark regions. We extended theoretical model for the transmissive phase-shift illumination approach in the case of a rectangular wave as the typical illumination pattern as the illumination pattern with finite-width dark regions and established the novel inspection method to discriminate defects with artificial textures. We confirmed that the rectangular-wave illumination enables us to selectively distinguish between defects and artificial textures.

An algorithm based on the Fourrier transformation and deconvolution of integrated images for optical diffraction tomography is described. There are some methods to retrieve the three-dimensional object distribution such as an imaging with longitudal scanning, computed tomography based on Radon transformation, digital holographic method and so on. A series of variable angle of plane wave illumination is typically used for diffraction tomography. In this paper, diffraction tomography with a one-dimensional series of images illuminated by arbitrary profile of the light sources. The estimated three-dimensional object distribution is accumulated so that the accuracy becomes better. Since we assume to use arbitrary illumination profiles, the accumulated distribution has a distortion. However, is possible to compensate the object distribution by employing the calculated point spread function obtained through the same procedure. As examples, the conventional plane-wave illumination and the point source illumination cases are introduced in association with the effect of the accumulation and deconvolution with the point spread function to the accuracy of the calculated object distribution.

Resonant MEMS mirror has been recognized as one of the solid-state laser beam steering (LBS) solutions for AR display and lidar. Such MEMS resonant mirrors’ large angular throw achieves over tens of degrees in scanning field of view (FOV) with operation speed exceeding tens of kHz in resonant frequency. In LBS, beam area is critical especially for lidar to access targets located at a far distance. Having both a large angular throw and beam area, or large Etendue, it is feasible to simultaneously satisfy requirement. For Time of Flight (ToF) lidar transmitter, we proposed and experimentally characterized a large Etendue LBS architecture employing a 2-dimensional MEMS mirror and diffractive LBS by Digital Micromirror Device (DMD). The beam area of MEMS resonant mirror is matched to DMD with relay optics while DMD diffractively increases the Etendue by factor of 5, which is equal to the number of diffraction orders supported by DMD. Along with beam steering, we address laser pulses’ timing to MEMS mirror’s movement to enable raster scanning that eliminates re-sorting of ToF data required for LBS employing a Lissajous pattern.

We demonstrated a real-time lidar system that utilizes a Digital Micromirror Device (DMD) as a field of view (FOV) expander and a 2D Multi-Pixel Photon Counter (MPPC) as a lidar sensor. By synchronizing the dynamic transition of DMD micromirrors between on- and off-states with the MPPC and a nanosecond pulse laser, the receiver FOV is diffractively steered to expected direction enabled by timing the delay of micromirrors transition to the laser. The DMD-MPPC lidar can capture up to 7 diffraction orders of high-resolution geospatial data. By applying the laser beam steering technique, this system is able to span over 35 degrees FOV, which is 10 times expansion of FOV compared to the single lidar detector FOV. In this work, as a preliminary demonstration towards diffractive FOV expansion, we presented the high resolution lidar images while DMD is switching between on and off state. Also, we performed distance resolution testing to validate the functionality of DMD-MPPC flash lidar system.

Holographic data storage is one powerful potential technology to solve the problem of mass data long-term storage. Deep learning is showing its advantages in many fields such as artificial intelligence, detection and imaging. When deep learning meets holographic data storage, new modulation ways and decoding methods were born. We did three kinds of modulation amplitude only, phase only and complex amplitude respectively in holographic data storage and used deep learning method to do data reconstruction. The results were better than previous reconstruction methods. Data reconstruction based on deep learning owns more anti-noise performance.

Amplitude-modulated collinear holographic data storage technology has high storage density, fast data transfer rate and stable system. The key to realizing system operation is to decode the amplitude code quickly and correctly. We proposed a decoding method based on 3:16 amplitude code. We used the convolution calculation to locate the sync mark point of every sub-page in the data page quickly and calculated the magnification rates among sub-pages to get the correct sub-page image segmentation. Taking the bit error rate as the evaluation standard, we verified our method successfully in different image quality.

The sealing method using a laser has been widely used since laser beams supplied locally the necessary energy to allow the formation of a hermetic bonding. The most common sealing techniques using a glass frit and a screen printer have some problems such as pores, non-uniform height, imperfect hermetic sealing. To reach high quality of laser sealing, the difference of coefficient thermal expansion (CTE) between the laser sealing glass and glass substrate should be lower than 1.0×10^-6/K. In order to prove the feasibility of novel laser sealing glass as a fiber type sealant, PbO-SiO₂-Al₂O₃-B₂O₃ based glass system was drawn with fiber types ranging from 180 μm to 1000 μm in diameter. CuO and Na₂CO₃ were added into PbO-SiO₂-Al₂O₃-B₂O₃ glass system in order to tuning the CTE. The thermo mechanical and thermal properties were investigated for correlations the CuO and Na₂CO₃ concentrations with PbO-SiO₂-Al₂O₃-B₂O₃ glass system. The 1wt% CuO and 1wt% Na₂CO₃ co-doped PbO-SiO₂-Al₂O₃-B₂O₃ glass system shows the CTE of 9.53×10^-6/K. In this study, the FTO-coated glass substrate with a CTE of 10.23×10^-6/K was sealed with fiber type sealant made of the CuO and Na₂CO₃ co-doped PbO-SiO₂-Al₂O₃-B₂O₃ glass system. These results indicate that the fiber type sealant is feasible as laser sealing material in the packaging industry.

The present work proposes and studies a table-top ¹²⁹Xe spin-exchange optical pumping polariser implementing a novel concept of interchangeable small-volume gas cells. The identified effect of relatively broadband medium absorption enabled efficient polarisation of ¹²⁹Xe nuclear spins within volumes of tens of millilitres by the radiation from commercial diode lasers with output powers of several W and the output line width of about 1 nm. Details of the developed device are presented, and its application in various industrial fields are discussed.

This PDF file contains the front matter associated with SPIE Proceedings Volume 12231 including the Title Page, Copyright information, Table of Contents, and Conference Committee Page.