为了实现短脉冲激光的高动态范围信噪比(SNR)测量,满足快点火对激光驱动器的要求,开展了信噪比测量的前期研究。结合非线性晶体分析了超短脉冲的二阶自相关信号的产生过程,结果表明自相关曲线的信噪比等于原始脉冲的信噪比。同时讨论了非共线二阶自相关中,两束输入信号光的夹角变化对输出信号光强的影响。在此基础上,建立了一台二阶自相关仪以验证超短脉冲信噪比测量系统的工作性能,其信噪比测量的动态范围达到了约108。

The signal-to-noise-retio (SNR) measurement is studied to achieve high dynamic range in pulse SNR measurement and meet the requirement of fast ignition of laser. The second order autocorrelation signal of short pulse occurring in nonlinear crystal is studied, which indicatesd that the pulse contrast of 2nd order autocorrelation equals that of original pulse. And the effect of the angle variation between two input beams on their output signal in non-collinear autocorrelation is discussed. A system of second order autocorrelation was built up to study the time characteristic of short laser pulse. Its dynamic range achieves ～108 in pulse contrast measurement.