Research On Damage Characteristics In Single-Crystal Silicon Irradiated By Long Pulse Laser

Single-crystal silicon (SCS) is an important infrared window material and structural material of detectors. As laser jamming and laser technology evolved, it is important to study the laser damage of SCS. Our main works are included as follows:According to the theory of heat conduction and thermoelasticity and assuming that SCS is isotropic and its thermal parameter is constant before and after the action of laser. With the different laser power density and irradiating time, the gauss long-pulse laser interaction with the SCS in the temperature distribution and thermal stress field were analyzed. And the temperature change was obtained in the laser irradiating center zone of SCS changes with time. The compressive strength of single-crystal silicon was far larger than the tensile strength, the material damage was mainly dependent on circle tensile stress.The laser-induced damage threshold (LIDT) of single-crystal silicon were investigated with a Nd:YAG laser at 1064nm under the 1-on-1 method and the 1000-on-1 method. Experiments showed that the LIDT of multi-pulse was lower than that of single-pulse for SCS as result of accumulative effect by the 1000-on-1 method. In this work, the damage Characteristics induced by guass long pulse laser under the different energy density was studied in detail. From the theoretical and experimental analysis, the explanation was obtained by thermal effect and thermal-stress coupling effect. Different amounts of long pulses were used in irradiating SCS till burning through the target. The laser-induced burning-through damage thresholds of different number of pulses have been got, and the multi-pulse cumulation factor of SCS was calculated to be about 0.912 by experimental data.The research results in this thesis can provide essential academic reference for laser jamming and laser protection.