采用1.319 μm和1.064 μm连续激光辐照硅基CCD,分析了红外激光入射引起的热效应导致的CCD材料的温度分布。计算结果表明随着温度的升高,暗电流不断增大,当温度超过340 K时,增大速度显著上升,暗电流噪声增大到可与串音阈值比拟。建立了不同功率密度激光入射CCD时探测响应模型,比较理想情况和热效应影响下探测响应模拟图。结果表明:由于激光辐照热效应引起的温度升高,进而引起暗电流噪声增大,严重影响CCD的成像效果。

1.319 μm and 1.064 μm laser were used to irradiate CCD image system. The temperature distribution of detector induced by infrared laser irradiating in the experiment above was simulated. The calculation results showed that with the rise of temperature, dark-current increased while pixel saturation threshold decreased. Especially, when temperature was higher than 340 K, the slope was extremely enhanced, and the order of dark-current noise was near to crosstalk threshold. A CCD physical model of crosstalk saturation was built and the response characteristics of CCD under the influence of thermal effect were analyzed. Result indicated that the rise of temperature induced by laser irradiating and the consequential changes of dark-current severely influenced imaging effect of CCD.