Polarization imaging is one of the important means of target detection and recognition, and the polarization device is the core of the system.In this paper, based on Stokes theory, a far infrared polarizing device---Two dimensional four direction array subwavelength double layer grating,is designed, which can be used for real-time measurement. Based on the equivalent medium theory, the size parameters of the micro unit are calculated.On the basis of the initial parameters, the micro cell structure is simulated and optimized.Finally, the simulation results show that the TM transmittance of the optimized double-layer grating structure is about 12% higher than that of the original one, reaching more than 90%,the extinction ratio is 25.8dB.
Laser damage identification is one of the hot research issues in recent years. Based on the mechanism of photothermal deflection, this paper established a physical model of reflective photothermal deflection based on laser damage.And designed an experimental test system for offset recognition based on the photothermal deflection method of the four-quadrant detector.The damage test of SiO2 film was carried out by the "1-0n-1" method specified by the national standard. The probe beam offset under different energies was studied, and the change trend of the detected beam offset during the damage of SiO2 film was analyzed.The optical properties and damage morphology of the samples were studied, and the damage threshold of SiO2 film was determined by zero probability damage threshold method.The experimental results show that when the SiO2 film is damaged by the photothermal deflection damage identification system based on the quadrant detector, when the offset is greater than 0.1mm, the SiO2 film is considered to be damaged, and the damage threshold is 12.7 J /cm2.The deviation of the test result based on the photothermal deflection damage offset of the four-quadrant detector and the test result of the phase contrast microscope method in the international standard ISO11254 is not more than 6.8%.
Aspheric optical elements are increasingly developing towards miniaturization. In the manufacturing process of aspheric lens, it is easy to produce warpage, deformation and other phenomena that affect the optical performance. In this paper, CAE technology is used to model it, and then finite element software is used to analyze its molding process. The effects of melt temperature, mold temperature, injection time, dwell pressure and cooling time on the internal stress of plastic parts are obtained, and the optimal injection parameters are obtained by optimizing the process parameters through orthogonal test. The lens quality is the best when the melt temperature is 300℃, the mold temperature is 80℃, the injection time is 1s, the dwell pressure is 60MPa, and the cooling time is 20s. The simulation results show that the maximum residual stress is 10.18MPa, which meets the requirements of the evaluation index and improves the product quality.
This paper adopts the method of numerical theoretical calculation and experimental simulation. The stress field characteristics under the interaction of 1064nm and 532nm composite pulse laser and single crystal silicon are studied and analyzed. Based on Fourier's heat conduction equation to establish a finite element model of single crystal silicon under composite pulse laser irradiation. Numerical simulation using simulation software, Analyze the stress field distribution generated during the action of single-crystal silicon material under the action of single-pulse laser and composite high-energy pulsed laser. Finally, the stress field distribution law under the irradiation of the composite high-energy pulsed laser is obtained, and when the pulsed laser acts on the target material, the stress field distribution range becomes larger, and the pressure value also increases, and the silicon material is more easily damaged. In order to solve the problem that the distribution of stress field affects the processing effect of monocrystalline silicon in the process of laser processing silicon.
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.