脉宽对中红外激光带内损伤HgCdTe材料的影响

研究了脉宽对于中红外脉冲激光带内损伤碲镉汞（HgCdTe）材料阈值的影响，使用一维自洽模型对激光辐照HgCdTe材料程中的载流子数密度，载流子对数目流，载流子对能流，载流子温度和材料晶格温度等相关参数进行仿真计算。仿真结果表明，波长2.85 μm，脉宽30 ps～10 ns单脉冲激光带内辐照HgCdTe材料的损伤阈值为200～500 mJ/cm2。其中，300 ps～3 ns脉冲激光的损伤阈值相近，均为200 mJ/cm2且低于其他脉宽激光的损伤阈值。搭建实验光路并进行相关实验验证仿真模型的正确性。实验发现，波长2.85 μm、脉宽300 ps的单脉冲激光带内辐照HgCdTe材料的损伤阈值在200 mJ/cm2左右。相同条件下，10 ns单脉冲激光带内辐照HgCdTe材料的损伤阈值约474 mJ/cm2。百皮秒脉冲激光对HgCdTe材料的损伤过程结合了热击穿和光学击穿效应，其独特的毁伤机理加剧了材料的损伤。

Influence of mid-infrared laser pulse width on in-band damage threshold of HgCdTe

To study the influence of pulse width on the damage threshold of HgCdTe material irradiated by mid-infrared in-band laser pulse, a one-dimensional model named self-consistent model is established. Some parameters including number density of carrier, carrier and energy current, temperature of carrier and lattice are calculated in the whole process. Damage thresholds of in-band single pulsed laser, whose wavelength is 2.85 μm and pulse width ranges from 30 ps to 10 ns, are obtained. The results show that, damage threshold rauge of in-band laser is 200?500 mJ/cm2. Among them, the damage threshold of 300 ps to 3 ns laser pulses is about 200 mJ/cm2, which is lower than that of other pulsed lasers. The validity of simulation model is verified by setting up the experimental devices and carrying out relevant experiments. Using a single pulsed laser with wavelength of 2.85 μm and pulse width of 300 ps as the light source, the damage threshold is about 200 mJ/cm2. Under the same conditions, when 10 ns single laser pulse is used, the damage threshold is greater than 474 mJ/cm2. The damage process of the HgCdTe material destroyed by hundred-picosecond pulsed laser combines thermal and optical breakdown effects, and its unique mechanism aggravates the destruction of material.