Adaptive optics are crucial for overcoming the fabrication limits on mirror curvature in high-precision interferometry. We describe a low-cost thermally actuated bimorph mirror with 200 mD linear response, which meets dynamic range and low aberration requirements for the $
mA + $A+ upgrade of the Laser Interferometer Gravitational-wave Observatory (LIGO). Its deformation and operation limits were measured and verified against finite element simulation.This work is devoted to the investigation of the enhancement of Raman signals of nonadsorbed gases in the vicinity of corrugated metallic surfaces supporting propagating surface plasmon-polaritons (PSPPs). Simulation of the PSPP excitation efficiency on holographic gratings coated with silver films of various thicknesses at different groove heights was carried out. Verification showed good agreement between theory and experiment. Also, it was found that an increase of the PSPP excitation efficiency may not lead to an increase in the enhancement factor of Raman signals of gases located near the surface-enhanced Raman scattering active surface. For a holographic grating with a period of 667 nm, a groove height of 70 nm, and a silver film thickness of 30 nm coated with a protective $
m Al_2
m O_3$Al2O3 layer, the enhancement factor of Raman signals of nonadsorbed nitrogen molecules was $sim
m 4cdot10^3$∼4⋅103.We report values of parametric-model (PM) parameters that can be used to obtain dielectric functions (refractive indices) from 1.5 to 6.0 eV for $
m In_x
m Al_1 - x
m P$InxAl1-xP alloys of arbitrary compositions $x$x. Using reported pseudo-dielectric data for several In compositions, we extract their dielectric functions by multilayer calculations, then parameterize them with PM lineshapes that well describe the asymmetric nature of their critical point (CP) contributions. We follow the $E_0$E0 fundamental bandgap as a function of $x$x, and determine the composition of the indirect-to-direct crossover.To eliminate the effect of tilt-shift error on the accuracy of phase-shifting interferometry (PSI), a fast and accurate tilt-shift-immune phase-shifting algorithm based on the self-adaptive selection of interferogram subblocks and principal component analysis (SSPCA) is proposed. First, each interferogram is divided into several subblocks, and principal component analysis and the least-squares method (LSM) are applied to obtain the phase-shift value of each subblock. Next, according to the correlation coefficients between each phase-shift curve, valid and invalid subblocks can be distinguished. Finally, all phase-shift values of the valid subblocks are used to fit the tilt phase-shift plane, and phase results can be obtained using the LSM. Simulations indicate that the accuracy of SSPCA can reach 0.03 rad both for small (1 rad) and large ($2pi $2π rad) tilt amplitudes, and it takes only one-tenth or less of the processing time of iterative algorithms. Experiments proved that SSPCA can be applied even without a precision phase shifter and thus provides a low-cost approach for PSI with both high precision and speed.Overlay target design is an important issue in overlay metrology, whose aim is to probe the optimal overlay target to achieve good performance on measurement precision and accuracy even in the presence of process variation. In this paper, the target design problem is first formulated as a multiobjective optimization problem and then solved by the multiobjective genetic algorithm. The feasibility of the proposed method is verified based on simulations carried out on two overlay targets. The results reveal that measurements with high precision, accuracy, and process robustness could be achieved on the targets designed by the proposed method.The novel two-dimensional (2D) elementary tellurium is currently of great interest in optoelectronic and photonic applications. In this contribution, 2D tellurium nanosheets were successfully created by using the liquid-phase exfoliation method. Selleck Adenine sulfate With the as-prepared tellurium nanosheets as the saturable absorber (SA), we realized a passively $ Q $Q-switched $
m Nd ext
m YVO_4$NdYVO4 laser operating at 1342 nm with a pulse width of 947 ns and single pulse energy of 2.25 µJ. Our work indicated the tellurium SA could be an efficient $ Q $Q-switcher for a near-infrared solid-state laser.A resolution-improved prism coupler-based surface plasmon resonance (SPR) sensor with a simple, effective rotational modulation method is proposed in this paper. For a conventional SPR sensor, the way to improve its measurement resolution is usually to use the rotating device with higher resolution. Measurement resolution depends on the modulation resolution of the incident angle; therefore, we propose a rotational modulation method that is implemented by rotating the prism horizontally to improve the modulation resolution of the incident angle, instead of using a more expensive rotating device with higher resolution. This scheme is validated both theoretically and experimentally. Furthermore, theoretical simulations show that the rotational modulation method can also be applied to long-range surface plasmon resonance sensors for better results.Synthetic aperture ladar (SAL) is a newly developed imaging device for remote sensing application. Owing to its short wavelength (3-5 orders of magnitude shorter than radar), SAL is very sensitive to platform vibration. For frequency-modulated continuous-wave SAL (FMCW-SAL), the platform vibration induces an additional range cell migration (RCM) to the SAL image. The vibration-induced RCM (VI-RCM) deteriorates the image quality. The VI-RCM is a unique problem for the FMCW-SAL imaging. To address this problem, a raw-data-driven method is proposed to correct the VI-RCM in this paper. First, the signal model was developed to show the VI-RCM in FMCW-SAL echo. Then, based on the model, the differential phase function (DPF) is constructed for the adjacent range profiles. The DPF is a single-frequency signal with its frequency being proportional to the relative range shift between the adjacent range profiles. Based on the DPF, the relative range shift is estimated. After the estimation of all the relative range shifts, the VI-RCM is calculated and corrected.Selleck Adenine sulfate