脉宽及重频对HgCdTe探测器损伤阈值影响分析

为了研究脉宽及重频对HgCdTe探测器损伤阈值影响，采用有限元法对HgCdTe红外探测器进行2维建模，以及激光辐照探测器温度场的仿真，得到了波段内外脉宽从10ns~1000ns的单脉冲激光损伤阈值。由于采用实验测定所有脉宽激光损伤阈值的办法不现实，故通过仿真计算，给出了从ns~μs量级不同激光脉宽的单脉冲探测器损伤阈值公式。结果表明，波段外单脉冲损伤阈值为9MW/cm2~0.9MW/cm2，波段内为150MW/cm2~15MW/cm2，并且探测器单脉冲损伤阈值与激光脉冲宽度呈负指数关系；当采用重频激光辐照探测器时，在相同的重复频率下，因长脉冲激光比窄脉冲宽激的脉冲间隔小，故长脉冲激光辐照时更容易出现温度积累效应，从而出现大面积损伤。这为进一步研究探测器的热应力场热弹性波和激光防护等提供了重要的理论分析依据。

Analysis of the influence of pulse width and repetition frequency on damage threshold of HgCdTe detector

In order to study the influence of pulse width and repetition frequency on the damage threshold of HgCdTe detector, finite element method was used to build 2-D model of HgCdTe infrared detector and the temperature field of laser irradiation detector was simulated. Damage threshold of single pulse laser of off-band and in-band was obtained from the range of 10ns to 1000ns. Measurement of damage threshold of all pulse width was hard. After simulation and calculation, the damage threshold formula from the range of 10ns to 1000ns was concluded. The results show that, single pulse laser damage threshold of off-band laser is 9MW/cm2~0.9MW/cm2, and 150MW/cm2~15MW/cm2 for in-band laser. And single pulse damage threshold has the negative exponential relationship with laser pulse width. And then, repetition frequency laser was used to irradiate detector with the same repetition frequency. The temperature accumulation effect and damages of large area are more likely to occur under long pulse laser irradiation, because pulse separation of long pulse laser is smaller than narrow pulse laser. The research is useful for studying stress field distribution、thermoplastic wave and laser protection.