全光固体条纹相机的理论及其静态实验研究

全光固体条纹相机采用空间调制抽运光激发平板波导光偏转器,通过精确控制抽运光和信号光之间的时间延迟,实现对入射到波导芯层信号光的偏转扫描.它能有效解决传统变像管条纹相机因空间电荷效应造成的动态范围降低以及光电阴极材料在红外波段探测受限等问题,且结构简单,系统稳定性高,理论时间分辨率可达皮秒甚至亚皮秒量级.本文围绕全光固体条纹相机的核心部件—–AlxGa1-xAs/GaAs/AlxGa1-xAs平板波导光偏转器,研究了在带填充效应、带隙收缩效应以及自由载流子吸收效应作用下GaAs折射率的变化情况;在GaAs折射率变化达到0.01量级,信号光束斑大小和波导宽度之比p=0.5时,得到系统的理论时间分辨率为2 ps;按照静态实验条件求得的理论空间分辨率为17 lp/mm,实验结果显示其值为9 lp/mm.

Theoretical and static experiment research on all optical solid state streak camera

All optical solid state streak camera is to carry out the process of deflecting and scanning of the signal light which is coupled into the core of the waveguide, with spatially-modulated pump pulse exciting the light deflector, through precisely controlling the time delay between signal light and pump light. Not only can it solve the problems existing in the traditional photoelectron streak camera such as the decrease of the dynamic range caused by space charge effect and incapability of detecting the infrared light signal for photoelectric cathode, but also it has the advantages of simple structure, systemic stability. And the theoretical temporal resolution can reach up to picosecond scale even sub picosecond scale. For the Al_xGa_1-xAs/GaAs/Al_xGa_1-xAs planar waveguide light deflector, we discuss in detail the change of the refractive index of the GaAs with time under the common influences of band filling, band gap shrinkage and free carrier absorption effect; when the change of the refractive index is on the order of 0.01 and the ratio of the signal spot size to the width of the waveguide p=0.5, the theoretical temporal resolution can reach 2 ps; finally, the theoretical spatial resolution is calculated to be 17 lp/mm according to the condition of static experiment, while the experimental results show that spatial resolution is 9 lp/mm.
Keywords： all optical solid state streak camera light deflector spatial resolution temporal resolution