Efficient generation of few-cycle pulses beyond 10 μm from an optical parametric amplifier pumped by a 1-µm laser system
Open Access
- 24 March 2022
- journal article
- research article
- Published by Springer Nature in Scientific Reports
- Vol. 12 (1) , 1-7
Abstract
Nonlinear vibrational spectroscopy profits from broadband sources emitting in the molecular fingerprint region. Yet, broadband lasers operating at wavelengths above 7 μm have been lacking, while traditional cascaded parametric frequency down-conversion schemes suffer from exceedingly low conversion efficiencies. Here we present efficient, direct frequency down-conversion of femtosecond 100-kHz, 1.03-μm pulses to the mid-infrared from 7.5 to 13.3 μm in a supercontinuum-seeded, tunable, single-stage optical parametric amplifier based on the wide-bandgap material Cd0.65Hg0.35Ga2S4. The amplifier delivers near transform-limited, few-cycle pulses with an average power > 30 mW at center wavelengths between 8.8 and 10.6 μm, at conversion efficiencies far surpassing that of optical parametric amplification followed by difference-frequency generation or intrapulse difference-frequency generation. The pulse duration at 10.6 μm is 101 fs corresponding to 2.9 optical cycles with a spectral coverage of 760–1160 cm−1. CdxHg1−xGa2S4 is an attractive alternative to LiGaS2 and BaGa4S7 in small-scale, Yb-laser-pumped, few-cycle mid-infrared optical parametric amplifiers and offers a much higher nonlinear figure of merit compared to those materials. Leveraging the inherent spatial variation of composition in CdxHg1−xGa2S4, an approach is proposed to give access to a significant fraction of the molecular fingerprint region using a single crystal at a fixed phase matching angle.Keywords
Funding Information
- Deutsche Forschungsgemeinschaft (GSC 1013 SALSA)
- Horizon 2020 Framework Programme (871124 Laserlab-Europe)
- Humboldt-Universität zu Berlin
This publication has 26 references indexed in Scilit:
- High-power sub-two-cycle mid-infrared pulses at 100 MHz repetition rateNature Photonics, 2015
- Frequency down-conversion of solid-state laser sources to the mid-infrared spectral range using non-oxide nonlinear crystalsProgress in Quantum Electronics, 2015
- Optical transitions due to native defects in nonlinear optical crystals LiGaS2Journal of Applied Physics, 2012
- BaGa_4S_7: wide-bandgap phase-matchable nonlinear crystal for the mid-infraredOptical Materials Express, 2011
- Growth and Characterization of BaGa4S7: A New Crystal for Mid-IR Nonlinear OpticsCrystal Growth & Design, 2008
- Nonlinear LiBIIICYI2 crystals for mid-IR and far-IR: Novel aspects in crystal growthJournal of Crystal Growth, 2008
- Quaternary Nonlinear Optical Crystals for the Mid-Infrared Spectral Range from 5 to 12 μm2008
- Ternary chalcogenides LiBC2 (B=In,Ga; C=S,Se,Te) for mid-IR nonlinear opticsJournal of Non-Crystalline Solids, 2006
- Mid-IR optical parametric amplification with femtosecond pumping near 800 nm using CdxHg1−xGa2S4Optics Communications, 2004
- Application of the solid solution CdxHg_1–xGa_2S_4 as a nonlinear optical crystalOptics Letters, 2002