Nanosecond MIR AgGaS_2 OPO and its Numerical Modelling

摘要

In this paper, we will report on a nanosecond mid infra-red AgGaS_2 (Type 1) optical parametric oscillator (OPO) with more than 4 micron output when pumped by nanosecond 1.064 micron Nd:YAG laser. Beside the experimental results, we will describe a numerical model to predict the conversion efficiency for this particular nanosecond configuration of singly resonating oscillator (SRO). This model is not only straightforward to implement but also gives adequate accuracy in its prediction. It takes into account the effects such as reduction in mode coupling due to Poynting vector walkoff and also the temporal dependence of the interacting waves. In addition, it can be easily extended to (a) doubly resonating oscillation (DRO), and (b) double pump pass version of both singly (SRO) and doubly (DRO) resonating oscillation in the nanosecond pulse regime. Good agreement with experimental results will also be shown.