Efficient, sub-4-cycle, 1-{\mu}m-pumped optical parametric amplifier at 10 {\mu}m based on BaGa4S7

TL;DR

This paper demonstrates a highly efficient, sub-4-cycle, 1-μm-pumped optical parametric amplifier at 10 μm using BaGa4S7, achieving broad spectral coverage and phase-stable pulses with potential for power scaling.

Contribution

It introduces a novel mid-infrared OPA based on BaGa4S7, showing superior efficiency and scalability compared to existing materials like LiGaS2.

Findings

Achieved 29% quantum efficiency at 10 μm

Generated 126-fs pulses covering 7.6-11.5 μm

Demonstrated power scaling potential with BaGa4S7

Abstract

We report on a {\mu}J-scale mid-infrared optical parametric amplifier (OPA) based on the recently developed wide-bandgap orthorhombic crystal, BaGa4S7 (BGS), and directly compare its performance to that of LiGaS2 (LGS) in the same OPA setup. The source is based on a single OPA stage amplifying supercontinuum seed pulses with a quantum efficiency of 29{\%} at an idler wavelength of 10 {\mu}m, featuring nominally carrier-envelope phase-stable pulses. As a result of pumping the OPA directly at 1 {\mu}m, the overall conversion efficiency far exceeds that of traditional schemes based on OPA's followed by difference frequency generation. Chirp compensation using bulk germanium resulted in 126-fs pulses covering the 7.6-11.5-{\mu}m spectral range. BGS holds great promise for power scaling due to its availability in larger single-crystal sizes than LGS.