Efficient half-harmonic generation of three-optical-cycle mid-IR frequency comb around 4 µm using OP-GaP.

Evgeni Sorokin,Robert L Byer,Irina T Sorokina,Alireza Marandi,M M Fejer,Peter G Schunemann

doi:10.1364/oe.26.009963

Abstract

We report a broadband mid-infrared frequency comb with three-optical-cycle pulse duration centered around 4.2 µm, via half-harmonic generation using orientation-patterned GaP (OP-GaP) with ~43% conversion efficiency. We experimentally compare performance of GaP with GaAs and lithium niobate as the nonlinear element, and show how properties of GaP at this wavelength lead to generation of the shortest pulses and the highest conversion efficiency. These results shed new light on half-harmonic generation of frequency combs, and pave the way for generation of short-pulse intrinsically-locked frequency combs at longer wavelengths in the mid-infrared with high conversion efficiencies.

Highlights

Broadband mid-infrared frequency combs are becoming increasingly important for applications such as trace gas sensing and stand-off molecular detection with high resolution, sensitivity, and fast acquisition rates [1,2,3]
We report a broadband mid-infrared frequency comb with three-optical-cycle pulse duration centered around 4.2 μm, via half-harmonic generation using orientation-patterned GaP (OP-GaP) with ~43% conversion efficiency
We reported a two-stage cascaded half-harmonic generation of three-optical-cycle pulses (

Summary

Introduction

Broadband mid-infrared frequency combs are becoming increasingly important for applications such as trace gas sensing and stand-off molecular detection with high resolution, sensitivity, and fast acquisition rates [1,2,3]. Some of the techniques to produce mid-infrared frequency combs includes difference frequency generation [4], synchronously-pumped optical parametrical oscillators (OPO) [5, 6], mid-IR femtosecond lasers [7], and microresonators [8]. Of these techniques, half-harmonic generation, i.e. the inverse of secondharmonic generation, using quasi-phase matched nonlinear media offers an unprecedented level of coherence transfer and efficiency [9,10,11]. In previous demonstrations of half-harmonic generation in the mid-IR, achieving high conversion efficiencies and few-cycle pulses simultaneously has been challenging due to the linear and nonlinear properties of available materials

Methods

Results

Conclusion