激光对HgCdTe的损伤降解研究

It is of great significance to research the laser irradiation effect and failure mechanism of the detector to optimize its performance. In this paper, the 512×1 linear array HgCdTe detector was used as the research object to study its damage phenomenon and mechanism. We used a picosecond pulsed laser with a wavelength of 1064 nm to irradiate the line array HgCdTe detector and found that some pixels of the detector were damaged when the laser energy density was greater than 700 mJ/cm2, and the damaged pixels showed different degrees of response without light conditions, but other undamaged pixels could respond normally. In one experiment, the detector was completely unable to respond normally when the laser energy was too large. To research the mechanism of laser-induced detector damage, we detected the damaged detector chip by using scanning electron microscopy and established a three-dimensional simulation model using COMSOL Multiphysics simulation software. Research showed that the temperature of the chip was too high and mercury was precipitated under high-energy laser irradiation, then the material composition changed and the resistance of the PN junction depletion layer changed accordingly, resulting in the damaged pixels showing different degrees of response without light conditions, but undamaged pixels could respond normally. When the readout circuit pin was damaged by a high-energy laser, the detector was completely unable to respond normally.

No abstract available

No abstract available

No abstract available

No abstract available

No abstract available

No abstract available

An analytical model for laser-induced damage under composite dual/multi-wavelength irradiation is established for a multilayer film. It is a field-thermal-stress coupled model that can predict the damage types under varying ratios of the fundamental harmonic (1ω) energy and its complementary third harmonic (3ω). Both the theoretical and experimental results revealed that the film damage is asymmetric on the front and rear surfaces. At a fixed total laser energy, the front surface primarily exhibited field-induced damage when the 1ω energy ratio reached 95%. However, as this ratio decreased to 92% or below, the front surface damage evolved into nanoscale fracture-type damage, dominated by field-stress coupling. In contrast, regardless of the energy ratio, damage sites on the rear surface consistently manifested as micrometer-scale remelted structures, dominated by thermal-stress coupling. The theoretical predictions agree well with experimentally observed damage morphologies and Raman spectral changes, validating the applicability and reliability of the model.

The thermal stress damage of optical elements always restrict the development of high power laser system. We studied the thermal damage mechanism of the optical elements with contaminants induced by high power continuous wave (CW) lasers. An experiment was carried out by a self-build optical element testing platform and a model based on the temperature field theory and thermodynamic theory was set up. We recorded the thermal stress damage process based on a 10 kW/cm2 level mid-infrared continuous wave laser. Then we calculated the thermal damage process of optical elements. The calculated results are in agreement with our experimental record. The results showed the success of modeling calculation in the thermal damage mechanism caused by contaminants.

In order to better study the damage effect of nanosecond pulsed laser on PIN photodiodes, a two-dimensional axisymmetric model and heat source model of nanosecond irradiation photodiodes were established according to the theory of heat conduction, and the factors of thermal physical parameters changing with temperature were considered. The finite element COMSOL Multiphysics software was used to simulate the temperature field distribution of PIN photodiodes irradiated by nanosecond pulse lasers. The research results show that the temperature change trend of the target surface under different energy densities is consistent, and there is a phenomenon of energy ac-cumulation. From the center of the irradiation to the edge of the target, the temperature gradually weakens and dis-tributes in a gradient. and the temperature rise rate of the target is directly proportional to the increase in energy density. It is found that the melting damage of the photodiode is reached. The range of energy density is, 144.01mJ/cm2 ~ 175.58 mJ/cm2 , The research results provide a theoretical basis for the research field of laser damage to materials.

No abstract available

No abstract available