基于InP的全光高速相机的理论和实验研究

Theoretical and experimental research on the all optical high-speed camera based on InP

为了评估基于瞬态光栅的全光高速相机系统中激发光强与图像信号之间的对应关系,验证基于磷化铟(InP)建立该相机的可行性。针对InP材料从理论上分析了从光子入射激发载流子,到载流子影响折射率,再到折射率影响衍射效率过程中各物理量值之间的关系;并建立了基于衍射光收集的图像探测系统获取InP内部的瞬态光栅分布图像。理论结果给出了针对InP材料的激发光强与载流子浓度的关系,探针激光为1064nm时载流子浓度与折射率之间的关系,以及瞬态光栅为矩形光栅时折射率与衍射效率之间的关系,特别指出在基于InP和1064nm探针激光的高速相机系统中,若时间分辨为1ps量级,对于532nm激发光,系统的灵敏度为1.3×105 W·cm-2量级。实验结果证明了基于InP和1064nm探针光可以建立全光高速相机系统,并根据所获得图像得出系统的空间分辨好于5.04lp/mm。

The research aims at assessing the relationship between the excitation light intensity and the image signal of the all optical high-speed camera system based on the transient grating and the viability of establishing a high-speed camera based on InP.This paper theoretically analyzes the physical quantity relationship of photons and excited carriers,carrier concentration and refractive index,refractive index and diffraction efficiency.In experiments,the image detection system based on collecting diffracted light was established to obtain the transient grating distribution in InP.Theoretical results provide the relationship between excitation light intensity and carrier concentration when the semiconductor is InP,the relationship between carrier concentration and refractive index when the wavelength of the probe beam is 1064 nm,and the relationship between refractive index and diffraction efficiency when the transient grating is rectangular grating.Theoretical results also indicate that the sensitivity of the all optical high-speed camera with 1ps time resolution based on InP and a probe beam of 1064 nm is about 1.3×10^5 W·cm^-2 when it is excited by the photons of 532 nm bean.Experimental results indicate that it is viable to establish all optical high-speed camera system based on InP and 1064 nm beam.According to the image obtained in experiments the spatial resolution of the system is better than 5.04lp/mm.