In this study, PbSe quantum dots (QDs) with subsequent characterization performed via X-ray diffraction (XRD) and transmission electron microscopy (TEM) were synthesized utilizing the thermal injection method. The absorption properties of the PbSe quantum dots were described using an ultraviolet-infrared spectrophotometer (UV-Vis), which shows that absorption in the range of 350 nm to 1600 nm, with an absorption typical peak near 1400 nm. Furthermore, the nonlinear optical properties of the quantum dots were systematically explored employing a femtosecond laser Z-scan system operating at a wavelength of 800 nm and a pulse width of 80 fs. As the incident laser power increasing, the nonlinear optical absorption behavior of the PbSe QDs underwent a discernible transition: from saturable absorption (SA) to reverse saturable absorption (RSA). By fitting the experimental data, the corresponding nonlinear absorption coefficients were determined -3.538×10-8 and 1.362×10-8 respectively. The transition power of the two absorption states occurs at approximately ~3.4 mW. This nonlinear optical absorption phenomenon of PbSe QDs presents applying in optical limiting technology, laser modulation technology, and photodetectors.
In this work, thermal injection was used to create CsPbBr1.8I1.2 perovskite Quantum Dots (QDs). The nonlinear optical characteristics and morphology of the quantum dots were characterized. A passively mode-locked Nd:YVO4 laser operating at 1064 nm was able to run consistently with the use of CsPbBr1.8I1.2 QDs SA. The passively mode-locked pulse output with a maximum output power of 287 mW and a repetition frequency of 80.645 MHZ was attained at a pump power of 3.3 W.
Based on the high photoluminescence quantum yield, broad absorption spectrum, and narrow symmetrical emission spectrum, perovskite quantum dots (QDs) have been adopted in pulsed laser generation as a saturable absorber, either organic or inorganic perovskites. In the paper, we improved the nonlinear absorption of CsPbBr3 QDs by non-covalent doping of Au particles, and the nonlinear absorption properties of the prepared Au-doped CsPbBr3 saturable absorber(SA) were characterized using the Z-scan system. A Q-switched laser output characteristics were obtained by building a Nd:YLF laser. We obtained a stable output average power of 815 mW and the minimum pulse width was 304ns. It shows that quantum dots can be modified to obtain better nonlinear coefficients by doping, showing potential application in the field of laser modulation.
Two-dimensional (2D) materials tin disulfide (SnS2) has been extensively researched in electronic, optoelectronic, energy storage, and conversion applications for large electronegativity, suitable band gap, earth abundance, and nontoxicity. In our work, the structure and nonlinear optical characteristics of SnS2 was characterized, and the performance of generating 1.34 μm ultrafast laser was explored. A 1.34 μm passively mode-locked Nd: Lu0.15Y0.85VO4laser is demonstrated based on a SnS2 saturable absorber prepared by a liquid phase exfoliation method. Owing to shorter upper-level lifetimes of the Nd: Lu0.15Y0.85VO4 mixed crystal, a passively Q-switched mode-locked (QML) laser was successfully realized at 1.34 μm. Under an absorbed pump power of 7.12 W, the mode-locked pulse as short as 25 ps was obtained with a repetition rate of 134 MHz and a maximum average output power of 651 mW at the corresponding laser spectral center of 1343 nm.
The application of two-dimensional (2D) materials as saturable absorbers (SAs) in ultrafast solid-state lasers has become a research hotspot due to its broadband absorption properties and simple fabrication process. However, the development of ultrafast solid-state lasers based on 2D material SAs is not mature, especially for mid infrared wavelengths. In this paper, the morphology and optical properties of zirconium pentatelluride (ZrTe5) are characterized. Using ZrTe5 as SAs, the picosecond continuous wave mode-locked (CWML) pulses with repetition frequencies of tens of MHz are obtained at 1 nm, 1.3 nm and 2 nm, respectively. The corresponding spectral centers are 1065.6 nm, 1343.3 nm and 2014.3 nm, respectively. For the 3 nm ultrashort laser, a passively mode-locked solidstate laser based on two-dimensional materials is realized for the first time, and a passively Q-switched mode-locked pulse with a pulse width of 800 ps and a repetition frequency of 180 MHz is obtained. Our results demonstrate the excellent modulation effect and great application potential of ZrTe5 in solid-state ultrafast lasers, which also proves the broadband absorption characteristics of ZrTe5.
We report the simulation of photonic crystals by holographic interference. In this article, different parameters such as azimuth angle, polarization angle, incident angle and phase degree are discussed, and the influences of them to interference patterns are studied. For 3 + 1 beams, the incidence angle influent the structure period, the phase degree doesn’t influent interference structure, the azimuth angle and polarization can change the structure. The azimuth angle change makes triangle claw structure elongate and intercourse and the polarization makes the contrast change. The simulation result paves a way for the optimized fabrication of structures by holographic lithography.
One method for measuring thin film thickness was proposed in this paper, which based on white light interference. One parallel flat crystal was used to be the standard glass, and put another glass on it, to form one air wedge between them. The reflectance spectrum of two beams interference was measured by one spectrometer. By fitting the reflectance spectrum, wave numbers corresponding to every peak can be found, then using two beam interference theory, the air gap thickness at light incident point can be fitted. By measuring the air gap thickness at different positions, the flatness of measured surface also can be analyzed.
We investigate the optical interference theory of double elliptically polarized beam (EPB) by using complex electric field amplitude vectors, compared with the real vectors for linearly polarized beam (LPB). Numerical simulations can show the differences between them quantitatively and qualitatively. Through altering parameters of double elliptically polarized beam interference configuration, different interference patterns are obtained. And it demonstrates its application potential in optical interference holographic set-up to fabricate optical micro-structures.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.