Tunable mid-infrared optical parametric oscillator with intracavity parametric amplification based on a dual-grating PPLN crystal

Abstract

Intracavity amplification of the idler radiation of a nanosecond optical parametric oscillator (OPO) is achieved within a single dual-grating PPLN crystal com- posed of a uniform-grating section followed by a fan-out grating section. While all the OPO wavelength-tuning capabilities are preserved, this configuration leads to a 60 % increase of the 4-lm idler power and a significant beam quality improvement when compared to a conven- tional singly resonant OPO.