GaAs/GaAlAs透射式光电阴极的分辨力特性分析

Resolution characteristic of GaAs/GaAlAs transmission photocathode

Ｇａ Ａｓ／ Ｇａ Ａｌ Ａｓ 透射式光电阴极的分辨力是第３ 代微光像增强器的重要参数之一。从简化的二维扩散方程推导了 Ｇａ Ａｓ／ Ｇａ Ａｌ Ａｓ 透射式阴极的调制传递函数（ Ｆｍ ，ｔ） ，计算了２ μｍ 厚 Ｇａ Ａｓ 阴极层的 Ｇａ Ａｓ／ Ｇａ Ａｌ Ａｓ 透射阴极的理论分辨力特性曲线，并讨论了它与若干参数的关系。据此得出在设计 Ｇａ Ａｓ／ Ｇａ Ａｌ Ａｓ 透射式光电阴极时应主要考虑最大量子效率，分辨力的损失并不限制系统的性能。

The resolution characteristic of GaAs/GaAlAs transmission photocathode is an important parameter in third generation intensifiers. The modulation transfer function of GaAs/GaAlAs transmission photocathode is derived from a simple two-dimensional diffusion equation. The theoretical resolution characteristics of a 2-μm-thick GaAs/GaAlAs transmission photocathode are calculated. The relationship between resolution and parameters in GaAs/GaAlAs transmission photocathode is discussed. A conclusion is drawn that one can design the GaAs/GaAlAs transmission photocathode for maximum quantum efficiency, since the sacrifice in resolution doesn't limit system performance.