We propose a theoretical method of pumping optimization for the Er-Yb laser based on the concept of a self-cooling laser. The pumping optimization realizes the anti-Stokes fluorescence cooling and excitation transfer by the Yb ions simultaneously. In this case, the Yb ions become the sources of cooling while the Er ions remain the heating sources. With a certain ratio between the cooling and heating sources, the operating temperature of the laser medium can be stabilized. We simulate the pumping process for the parameters of the Er, YbYAG system to demonstrate the possibility of getting a thermally stabilized operating mode of the laser for the ion ratios in the range of 40 to 60 Yb ions to one Er ion. The simulations show that the self-cooled laser medium can be implemented for the laser intensities of kW/cm2 in the cavity.A plane wave aspheric surfaces test is simpler and easier to assemble than a spherical wave test. An optical system combining Dall with Offner null compensation using a plane wave is proposed for measuring large-aperture and large-relative-aperture aspheric concave surfaces. One back compensation lens and one front compensation lens are used in the system, which can realize a high-precision null test. Based on the third-order aberration theory, the normalized theoretical parameters are calculated by formula derivation, and then are optimized after analysis. The design characteristic is compared with the classical plane wave Offner null test. A prototype experiment of the proposed method is carried out with a parabolic mirror of 500 mm diameter, at relative aperture 1/1, showing that RMS surface error of λ/40 can be obtained.In order to measure the grating constants of different types of holographic samples efficiently and conveniently, we use spectrophotometers and the macro angle-resolved spectrum system to measure spectral information from six different holographic samples with three types, including rainbow holographic samples with light pillars, plain rainbow holographic samples, and matte holographic samples with light pillars. The information obtained from the instruments was used to investigate their grating constants by the grating equation. It was found that for the grating constant calculation, compared with the values measured using a light optical microscope, the angle-resolved spectrum system and the 45/0 spectrophotometers were applicable to the samples with rainbow effects. For the matte holographic samples, the angle-resolved spectrum system, which was mainly used to distinguish the differences between different matte samples, was necessary. The results from the spectrometric methods were similar to those from the light optical microscope.This paper presents the design of a wideband polygonal directional beam antenna based on the ray inserting method. The wideband characteristic of the directional beam antenna is achieved thanks to the use of inhomogeneous dielectric material. Also, unlike most previous works, the present design can be implemented with the isotropic and above unity refractive index materials, consequently simplifying its fabrication process. The finite difference time domain scheme is used to evaluate the directional beam antenna.Measuring the spectral response (SR) of large-area (>100cm2) luminescent solar concentrators (LSCs) has proven difficult because common laboratory photovoltaic (PV) instruments that offer monochromatic incidence measure devices with limited sizes (typically less then 50cm2).  https://www.selleckchem.com/products/bp-1-102.html  This report addresses this issue through a method called regional measurements. In this method, large-area LSCs are configured to small surface and edge regions, which are sequentially illuminated and measured, respectively. The measured SRs of large-area LSCs are consistent with those from the conventional method and the Monte Carlo ray-tracing simulation. This method is also applied to analyze scattering effects in the LSCs, showing the relationships of the scattering-induced power gain and power loss to the surface root-mean-squared roughness (Rq) of the devices. The results explain why the PV performance of the LSCs can be improved through proper surface scattering treatment.We proposed and demonstrated a method to fabricate ultrashort all-fiber Fabry-Perot interferometers by splicing a standard single-mode fiber and another single-mode fiber with a concave surface constructed by a CO2 laser pulse. The geometric parameters of the concave surface could be controlled flexibly by adjusting the laser pulse and the relative position between the laser beam and the optical fiber. In our experiments, the minimum depth of the concave surfaces is 0.12 µm, which offers a means of fabricating an all-fiber Fabry-Perot interferometer with submicrometer cavity length. Moreover, the ultralow-roughness concave surface fabricated by a CO2 laser pulse is beneficial to improve the fringe visibility of the interferometer. These advantages make it attractive for practical applications.The photoelasticity of the Ca3TaGa3Si2O14 (CTGS) crystal was studied by an interferometric method based on a single-pass Mach-Zehnder interferometer. The maximum number of sample orientations for the piezo-optic experiments was applied to prove accuracy in the determination of the piezo-optic coefficients. Based on the matrices of the piezo-optic coefficients and the elastic stiffness coefficients, all the coefficients pik of the elastic-optic matrix are calculated. For the highest pik coefficient, the acousto-optic efficiency is evaluated. The results obtained for CTGS are compared with the corresponding results for La3Ga5SiO14 (langasite) crystals. The highest acousto-optic figure of merit of CTGS M2=1.66⋅10-15s3/kg is two and three times higher, compared with langasite and strontium borate, respectively, which are often used for acousto-optic modulation of light in the ultraviolet spectral range.In many commercial instruments for measuring reflectance, the area illuminated on the measured object is identical to the area from which light is collected. This configuration is suitable for strongly scattering materials such as paper, but issues arise with translucent materials, because a portion of the incident light spreads around the illuminated area by subsurface transport and escapes the detection system. This phenomenon, referred to as edge loss, yields erroneous, underestimated reflectance measurements. In the case of colored and opalescent materials, the impact of edge loss on the measured reflectance varies with the wavelength, which is a significant issue for spectrophotometer and colorimeter users. In the present study, we investigate the edge-loss phenomenon with an emphasis on human skin measurement. In particular, we use a mathematical model to estimate the PSF of translucent materials, relying on the diffusion approximation of the radiative transfer theory, to predict edge-loss measurement error.