Refined Sellmeier equations for AgGaS2 down to 0.565 µm.

We revisit the 90° phase-matching conditions for second-harmonic, sum-frequency, and difference-frequency generation in A g G a S 2 thus far reported in the literature. We present refined Sellmeier equations coupled with an updated thermo-optic dispersion formula to correctly reproduce the experimental results for noncritical three-wave interactions obtained in the 0.565-10.5910 µm spectral range.

Efficient generation of few-cycle pulses beyond 10 µm from an optical parametric amplifier pumped by a 1-µm laser system.

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.

Temperature-dependent phase-matching properties of BaGa2GeS6 in the 0.767-10.5910 µm spectral range.

We report experimental results on the temperature-dependent phase-matching properties of BaGa2GeS6 for second-harmonic generation and sum-frequency generation in the 0.7674-10.5910 µm range. We also derive refined Sellmeier and thermo-optic dispersion formulas that provide a good reproduction of the present experimental results.

Refined Sellmeier equations for BaGa4S7.

This paper reports refined Sellmeier equations for the biaxial nonlinear crystal BaGa4S7 that provide a good reproduction of the phase-matching angles for second-harmonic generation (SHG) and sum-frequency generation (SFG) of the mid-IR outputs of Nd:YAG and Ho:YLF laser-pumped optical parametric oscillators (OPOs) and a frequency-doubled CO2 laser in the 0.7584-8.018 µm range. The theoretical results are found to agree with the recent experimental data for 1-µm-pumped optical parametric processes based on BaGa4S7 beyond 8 µm.

Refined Sellmeier equations for AgGaSe2 up to 18 µm.

We present refined Sellmeier equations for AgGaSe2 that provide good reproduction of the phase-matching angles for frequency upconversion of CO2 laser radiation in the 1.7652-10.5910 µm range and for frequency downconversion in the 1.85-18 µm range thus far reported in the literature.

Effective nonlinearity of the new quaternary chalcogenide crystal BaGa2GeSe6.

The unknown magnitude and relative signs of the trigonal crystal ${\rm BaGa}_{2}{\rm GeSe}_{6}$BaGa2GeSe6 nonlinear coefficients have hindered defining an optimum orientation for maximum frequency conversion efficiency. This issue is resolved in the present work, obtaining ${d_{11}}= + {23.6}$d11=+23.6, ${d_{22}}= - {18.5}$d22=-18.5, and ${d_{31}}= + {18.3}\;{\rm pm/V}$d31=+18.3pm/V for frequency doubling of the 10.591 µm radiation.

Thermo-optic dispersion formula for BaGa2GeSe6.

A thermo-optic dispersion formula for ${{\rm BaGa}_2}{{\rm GeSe}_6}$BaGa2GeSe6 nonlinear crystal is reported. The experimentally determined temperature-dependent phase-matching conditions for second-harmonic and sum-frequency generation of Nd:YAG laser-pumped ${{\rm KTiOPO}_4}$KTiOPO4 (KTP) and ${{\rm RbTiOAsO}_4}$RbTiOAsO4 (RTA) optical parametric oscillators as well as a ${{\rm CO}_2}$CO2 laser and its harmonics in the 0.805-10.5910 µm range are precisely reproduced by the formula when combined with the Sellmeier equations previously reported by the present authors [Appl. Opt.57, 7440 (2018)APOPAI0003-693510.1364/AO.57.007440].

Thermo-optic dispersion formula for LiGaS2.

This paper reports on new experimental results on the temperature-dependent phase-matching properties of LiGaS2 for second-harmonic generation and sum-frequency generation in the 0.820-10.5910 µm spectral range. In addition, we present a thermo-optic dispersion formula that provides a good reproduction of the present experimental results when combined with the Sellmeier equations presented in our previous paper, Kato et al. [Opt. Lett.42, 4363 (2017)OPLEDP0146-959210.1364/OL.42.004363].

Phase-matching properties of BaGa2GeSe6 for three-wave interactions in the 0.778-10.5910 µm spectral range.

We present new experimental results for the phase-matching properties of the recently discovered BaGa2GeSe6 crystal for harmonic generation of a Nd:YAG laser-pumped KTP OPO and a CO2 laser in the 0.778-10.5910 µm spectral range. In addition, we present new Sellmeier equations that provide a good reproduction of the present experimental results as well as the published data points for SHG of a CO2 laser at 10.5910 µm and a 1.85 µm-pumped OPO in the 2.156-3.220 µm and 4.348-13.035 µm spectral ranges.

Thermo-optic dispersion formula for BaGa4Se7.

This paper reports on the thermo-optic dispersion formula for BaGa4Se7 that provides a good reproduction of the temperature-dependent phase-matching conditions for type-1 and type-2 second-harmonic generation of a Nd:YAG laser-pumped AgGaS2 optical parametric oscillator (OPO) and a CO2 laser in the 0.901-10.5910 µm spectral range, as well as the published data points for a Nd:YAG laser-pumped OPO at λi=3.9040 µm when combined with the Sellmeier equations of the present authors [Appl. Opt.56, 2978 (2017)APOPAI0003-693510.1364/AO.56.002978].

Phase-matching properties of LiGaS2 in the 1.025-10.5910 µm spectral range.

This Letter reports on the new experimental results for second-harmonic generation and sum-frequency generation in LiGaS2 in the 1.025-10.5910 µm range, together with the new Sellmeier equations, which provide a good reproduction of the present experimental results, as well as the published data points for a Ti:Al2O3 laser (λ=0.8200 µm)-pumped optical parametric amplifier in the 3.7434-11.0079 µm range and a Nd:YAG laser-pumped optical parametric oscillator at ∼5.457 µm.

Phase-matching properties of LiGaSe2 for SHG and SFG in the 1.026-10.5910 µm range.

This paper reports on the new experimental results for second-harmonic generation and sum-frequency generation in LiGaSe2 in the 1.026-10.5910 µm range, and the improved Sellmeier equations that provide a good reproduction of the present experimental results, as well as the published data points for a Ti:Al2O3 laser (λ=0.8200 µm)-pumped optical parametric amplifier and a Nd:YAG laser-pumped optical parametric oscillator in the mid-IR.

Phase-matching properties of BaGa4Se7 for SHG and SFG in the 0.901-10.5910 µm range.

We report new experimental results on the phase-matching properties of a BaGa4Se7 crystal for harmonic generation of a Nd:YAG laser-pumped AgGaS2 optical parametric oscillator (OPO) and a CO2 laser in the 0.901-10.5910 µm range. In addition, we present new Sellmeier equations that provide a good reproduction of the present experimental results as well as the published data points for a Nd:YAG laser-pumped OPO and an optical parametric amplifier (OPA) in the 3.10-15.22 µm range and a Ho:YAG laser-pumped OPA in the 3.49-5.18 µm range.

Phase-matching properties of yellow color HgGa2S4 for SHG and SFG in the 0.944-10.5910 µm range.

We report new experimental results on the phase-matching properties of yellow color HgGa2S4 crystals for harmonic generation of an Nd:YAG laser-pumped KTiOPO4 (KTP) optical parametric oscillator (OPO) and CO2 lasers in the 0.944-10.5910 µm range. In addition, we present new Sellmeier equations that provide a good reproduction of the present experimental results as well as the published data points for second-harmonic generation of CO2 laser radiation at 9.2197-9.6392 µm and Nd:YAG laser-pumped OPOs at 1.205-1.725 µm and 2.77-9.10 µm that were achieved with the orange and yellow color crystals.

Sellmeier and thermo-optic dispersion formulas for the extraordinary ray of 5 mol. % MgO-doped congruent LiNbO(3) in the visible, infrared, and terahertz regions.

This paper reports the high-accuracy Sellmeier and thermo-optic dispersion formulas for the extraordinary ray of 5 mol. % MgO-doped congruent LiNbO(3) that provide excellent reproduction of the temperature-dependent quasi-phase-matching conditions in the 0.39-4.95 µm and 150-270 µm ranges. We believe that these equations would be highly useful for designing the frequency conversion system based on periodically poled MgO-doped LiNbO(3)

Set of Sellmeier equations for GaS and GaSe and its applications to the nonlinear optics in GaS(x)Se(1-x).

This paper reports a set of Sellmeier equations for GaS and GaSe that provide excellent reproduction of the phase-matching conditions for second- to sixth-harmonic generation of CO2 laser radiation at 10.5910 µm in GaS(0.4)Se(0.6) at 20°C. In addition, this set of Sellmeier equations is found to reproduce well the phase-matching angles for second-harmonic generation of a Ti:Al2O3 laser-pumped BaB2O4 optical parametric generator at 2.14-2.9 µm and CO2 laser radiation at 9.2(9.2007)-10.7(10.6746) µm measured by Kang et al. [Appl. Phys. B 108, 545 (2012)] in GaS(0.09)Se(0.91) and GaS(0.41)Se(0.59).

Sellmeier and thermo-optic dispersion formulas for LiInSe2.

This paper reports on the improved Sellmeier and thermo-optic dispersion formulas for LiInSe2, which provide a good reproduction of the temperature-dependent phase-matching conditions for the nonlinear frequency-conversion experiments achieved in the 1.0642-10.5910 µm range.

Sellmeier and thermo-optic dispersion formulas for LiInS(2).

This paper reports on improved Sellmeier and thermo-optic dispersion formulas for LiInS2, which provide an excellent reproduction of the temperature-dependent phase-matching conditions for second, sum-, and difference-frequency generation achieved in the 1.0642-10.5910 µm range.

Sellmeier and thermo-optic dispersion formulas for GaSe (Revisited).

This paper reports high-accuracy Sellmeier and thermo-optic dispersion formulas for GaSe that provide excellent reproduction of the phase-matching conditions for second-, third-, and fourth- harmonic generation of CO2 laser radiation at 10.5910 µm in the 20°C-200°C range as well as the data points of Feng et al. [Opt. Express16, 9978 (2008)10.1364/OE.16.009978OPEXFF1094-4087] for second-harmonic generation of CO2 laser radiation at 9.5862 µm and an Er3+:YSGG laser at 2.7960 µm in the -165°C-230°C range.

Sellmeier equations for GaS and GaSe and their applications to the nonlinear optics in GaSxSe(1-x).

The Sellmeier equations for GaS and GaSe are constructed from the nonlinear experiments thus far reported in the literature. The model calculations based on these equations were found to reproduce well the phase-matching conditions for second-harmonic generation of the Er:YSGG laser at 2.7960 µm and the CO2 laser lines at 9.5862 and 10.5910 µm achieved in the GaSxSe(1-x) crystals having different S concentrations of 0.004-0.412.