Based on the Richards-Wolf vector diffraction integration, we obtained the expressions of the intensity and velocity of femtosecond radially polarized pulses at the focus near a dielectric interface, and the pulses are modulated by an optical system consisting of diffractive optical elements (DOEs) and a high numerical aperture (NA) lens. The factors that affected the intensity distribution and velocity evolution of the three-dimensional optical capture structural pulse (optical chain) are also analyzed. These factors include the DOE structural parameters (bandwidth, phase difference between the rings), the interception ratio of incident beam, the NA, the central wavelength of pulses, and the refractive index of exiting medium. The results show that the velocity of the optical chain will increase with an increase in the DOE bandwidth or a decrease in the refractive index of the exiting medium, and the maximum of the optical chain velocity will decrease versus the NA. Furthermore, the dependence of the optical chain velocity on its intensity distribution is also revealed. The superluminal and subluminal can also be found during the propagation of the optical chain. The velocity distribution difference between bright and dark areas along the z axis is more conducive to distinguishing the trapping of the Rayleigh particles. We believe these interesting results have great potential to improve the space-time resolution to detect particle positions during high-speed optical trapping.A star tracker should be well calibrated before it is equipped in order to achieve high accuracy. There exists, however, the coupling problem between the internal and external parameters for most commonly used laboratory calibration methods, which affect the star tracker's performance. We theoretically analyze the major aspects of the coupling mechanism based on the star tracker laboratory calibration model, which means the coupling between the principal point and the installation angle. The concept of equivalent principal point error, which illustrates the effectiveness of the calibration even with poor decoupling accuracy between the principal point and the installation angle, is introduced. Simulation and bench experiments are conducted to verify the laboratory calibration method and its coupling mechanism. The decoupling accuracy can be improved with more samples during calibration. In addition, the equivalent principal point error converges quickly and hardly affects the attitude of the star tracker, which is verified by both theory and experiment. The comprehensive calibration accuracy can still reach a high level even with poor decoupling accuracy.Three-dimensional (3D) shape measurement systems based on diffuse reflection of projected structured light do not deliver reliable data when measuring glossy, transparent, absorbent, or translucent objects. In recent years, we have developed a method based on stereo recording with infrared cameras and projection of areal aperiodic sinusoidal thermal patterns to detect such objects. However, the measurements took longer than 10 s, up to minutes; moreover, the measurement accuracy was improvable. Now, we have succeeded in both drastically reducing measurement time and significantly increasing measurement quality. This finally provides a technique for reliably measuring transparent objects, e.g., in series production. We demonstrate measurement examples achieved within 1 s and with 3D standard deviations less than 10 µm.In recognition of the misuse risks of fentanyl, there is an urgent need to develop a useful and rapid analytical method to detect and monitor the opioid drug. The surface-enhanced shifted excitation Raman difference spectroscopy (SE-SERDS) method has been demonstrated to suppress background interference and enhance Raman signals. In this study, the SE-SERDS method was used for trace detection of fentanyl in beverages. To prepare the simulated illegal drug-beverages, fentanyls were dissolved into distilled water or Mizone as a series of test samples. Based on our previous work, the surface-enhanced Raman spectroscopy detection was performed on the beverages containing fentanyl by the prepared AgNPs and the SE-SERDS spectra of test samples were collected by the dual-wavelength rapid excitation Raman difference spectroscopy system. In addition, the quantitative relationship between fentanyl concentrations and the Raman peaks was constructed by the Langmuir equation. The experimental results show that the limits of quantitation for fentanyl in distilled water and Mizone were 10 ng/mL and 200 ng/mL, respectively; the correlation coefficients for the nonlinear regression were as high as 0.9802 and 0.9794, respectively; and the relative standard deviation was less than 15%. Hence, the SE-SERDS method will be a promising method for the trace analyses of food safety and forensics.A number of acousto-optic figures of merit and elasto-optic constants of a mercury bromide (Hg2Br2) crystal were measured. https://www.selleckchem.com/products/gw6471.html The key characteristics of the wide-angular acousto-optic tunable filter based on a Hg2Br2 crystal in the (11¯0) plane were calculated from the measurements carried out and previously known data. It is demonstrated that the crystal makes it possible to create effective devices operating in the 5-25 µm wavelength range. In addition, we proposed the design of a filter operating in the long-wavelength infrared range of 8-12 µm, providing spectral resolution up to R=300 and a field of view outside the crystal up to 10°. Its diffraction efficiency can reach up to 2% per 1 W of continuous driving power.Free-space optical measurement systems can have a direct impact on evaluation systems operational in propagation paths. During propagation via optical fibers, light suffers scattering or interference, causing some output signal loss with an uncertainty outcome. Therefore, this study aims to explore the instant decisions related to the use of single- and multi-mode fiber optics and how they affect the gathering of data from high-speed optical measurement instrument links. The study also seeks to address a number of design methodology aspects and the empirical outcomes related to a surface topography measurement sensor based on fiber optics capable of surface roughness or step-height measurement. The study suggests that the Fourier transform profilometry method (FTP) can overcome the disadvantages of optical metrology sensors (e.g., bulkiness, challenging set-up, high costs, and low speed). However, despite eliminating vertical height problems, the Fourier transform profilometry (FTP) did have some shortcomings for every outcome related to core variables, including the dispersive optical fiber link sensor.