Thermo-optic Dispersion Formulas Research Articles

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 0.565-10.5910µm spectral range.

Refined Sellmeier and thermo-optic dispersion formulas for BaGa4Se7

This paper reports on the refined Sellmeier and thermo-optic dispersion formulas for BaGa4Se7 that provide a good reproduction of the temperature-dependent phase-matching conditions for type-2 difference-frequency generation between the signal and idler outputs of a Nd:YAG laser-pumped KTiOPO4 optical parametric oscillator in the 8.457–9.092 µm and 12.075–14.201 µm spectral ranges at 20–150°C and recent experiments within these wavelength and temperature ranges performed by other authors.

High efficiency non-critical phase-matching 9.3–10.6 μm optical parametric oscillator in BaGa4Se7 crystal

In this letter, a non-critical phase-matching (NCPM) BaGa4Se7 (BGSe) optical parametric oscillator (OPO) was demonstrated with a home-made acousto-optic (AO) Q-switched Ho:YLF laser as the pump source. The idler wavelength tunability was recorded to be 9393.3 to 10627.4 nm with BGSe crystal temperature varying from 45 to 5 Celsius (˚C), corresponding to an average wavelength adjustment of 30.85 nm/˚C. Up to 200 mW of idler average output power at 10219 nm was obtained with pulse repetition frequency (PRF) at 200 Hz, the slope efficiency and pump-to-idler efficiency are 8.04 % and 5 %, respectively. In addition, in the angle tuning experiment, a refined Sellmeier Equation (S-E) was derived based on the discrepancy between the experimental data and the theoretical calculations based on the existing S-Es. However, it was found that the deviations between experimental measurement data and theoretical calculations in NCPM experiment were still too large to be ignored after using the refined S-E. Probably, the phenomenon was caused by the thermo-optic dispersion formula dn/dT provided by references were not precise enough for describing NCPM BGSe crystal in waveband ∼ 10 μm.

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 0.7674-10.5910µm range. We also derive refined Sellmeier and thermo-optic dispersion formulas that provide a good reproduction of the present experimental results.

Phase-matching properties of Ba2Ga8GeS16

We report experimental results on the phase-matching properties of the quaternary B a 2 G a 8 G e S 16 crystal for second-harmonic generation (SHG) and sum-frequency generation (SFG) of Nd:YAG laser-pumped K T i O P O 4 (KTP) and H g G a 2 S 4 (HGS) optical parametric oscillators (OPOs) and a waveguide C O 2 laser in the 0.8054–10.5910 µm range. Based on these experimental data, we derive refined Sellmeier equations and thermo-optic dispersion formulas that are expected to enable practical applications of this new uniaxial nonoxide nonlinear crystal in the mid-IR part of the spectrum.

Anisotropy of thermo-optic properties of beryllium hexaaluminate crystal doped with chromium ions

We determined the thermo-optic coefficients of C r 3 + -doped beryllium hexaaluminate crystal ( C r 3 + : B e A l 6 O 10 ) for light polarizations E | | N p , N m , and N g , and present the thermo-optic dispersion formulas for the principal thermo-optic coefficients of C r 3 + : B e A l 6 O 10 . We also measured the linear thermal expansion coefficients for this crystal in the directions of optical indicatrix axes N p , N m , and N g . Finally, we modeled the thermo-optic dispersion data in accordance with theory, taking into account contributions both from the change of the electronic bandgap with temperature and from the volumetric thermal expansion coefficient.

Thermo-optic dispersion properties of CdSe for parametric nonlinear interactions

Temperature tuning of CdSe optical parametric oscillators (OPO’s) is studied by pumping with the 1.8645-µm signal and 2.4793-µm idler outputs of a Nd:YAG laser-pumped CsTiOAsO4 (CTA) OPO. The measured temperature-dependent phase-matching conditions are used to construct new Sellmeier and thermo-optic dispersion formulas for CdSe, which are verified via temperature-tuned sum-frequency generation (SFG) between the fundamental and second harmonic of a transversely excited atmospheric (TEA) CO2 laser operating at 10.2466, 9.5525, and 9.2714 µm.

Anisotropy of thermo-optic properties of beryllium hexaaluminate crystal doped with chromium ions

We determined the thermo-optic coefficients of Cr3+-doped beryllium hexaaluminate crystal (Cr3+:BeAl6O10) for light polarizations E||Np, Nm, and Ng, and present the thermo-optic dispersion formulas for the principal thermo-optic coefficients of Cr3+:BeAl6O10. We also measured the linear thermal expansion coefficients for this crystal in the directions of optical indicatrix axes Np, Nm, and Ng. Finally, we modeled the thermo-optic dispersion data in accordance with theory, taking into account contributions both from the change of the electronic bandgap with temperature and from the volumetric thermal expansion coefficient.

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].

Temperature-dependent quasi phase-matching properties of periodically poled LaBGeO5

We report accurate Sellmeier equations at 22℃ for LaBGeO5, which reproduce well our experimental results for the quasi phase-matching conditions with the ee-e, oe-o, eo-o, and oo-e interactions in the 0.2660 − 1.0642 µm spectral range. In addition, the thermo-optic dispersion formula (dn/dT) of this material is also presented.

New Sellmeier and Thermo-Optic Dispersion Formulas for AgGaS2

This paper reports on the new Sellmeier and thermo-optic dispersion formulas that provide a good reproduction of the temperature-dependent phase-matching conditions for second-harmonic generation (SHG) and sum-frequency generation (SFG) of a CO2 laser and a Nd:YAG laser-pumped KTiOPO4 (KTP) optical parametric oscillator (OPO) in the 0.8859–10.5910 μm range as well as those for difference-frequency generation (DFG) between the two diode lasers in the 4.9–6.5 μm range and DFG between the two periodically poled LiNbO3 (PPLN) OPOs in the 5–12 μm range thus far reported in the literature.

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 0.820-10.5910μm 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 etal. [Opt. Lett.42, 4363 (2017)OPLEDP0146-959210.1364/OL.42.004363].

Dispersion and anisotropy of thermo-optical properties of Alexandrite laser crystal

Dispersion and anisotropy of thermal coefficients of the optical path (TCOP) and thermo-optic coefficients (TOCs) of Alexandrite laser crystal (Cr3+:BeAl2O4) are studied for the three principal light polarizations, E || a, E || b and E || c. Thermo-optic dispersion formulas are presented for the spectral range of 0.4-1.1 µm. All TOCs are positive and show a notable polarization-anisotropy, dna/dT = 5.9, dnb/dT = 6.9 and dnc/dT = 15.2 × 10−6 K−1 at 0.75 µm. Thermal lensing was characterized in a continuous-wave Alexandrite laser pumped at 0.532 µm and operating at 0.7509 µm (for E || b). The measured thermal lens was weak, positive and slightly astigmatic. The sensitivity factors of the thermal lens were found to be Mx = 1.74 and My = 2.38 [m−1/W].

New thermo-optic dispersion formula for LiB3O5

This paper reports on the new thermo-optic dispersion formula for LiB3O5 that provides a good reproduction of the temperature dependent phase-matching conditions for second-harmonic generation, sum-frequency generation, and optical parametric oscillator thus far reported in the literature when combined with the Sellmeier equations presented in the previous paper (Kato 1994 IEEE J. Quantum Electron. 30 2950–2).

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 0.901-10.5910μm 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].

Sellmeier equations, group velocity dispersion, and thermo-optic dispersion formulas for CaLnAlO4 (Ln = Y, Gd) laser host crystals.

We studied the refractive index and dispersive properties of the tetragonal rare-earth calcium aluminates, CaLnAlO4 (Ln=Gd or Y). Sellmeier equations were derived for the spectral range of 0.35-2.1μm. The group velocity dispersion (GVD) in CaGdAlO4 is positive at ∼1 μm, 95 fs2/mm and negative at ∼2 μm, -40 fs2/mm. The GVD values for CaYAlO4 are similar. In addition, thermo-optic coefficients, dn/dT, and thermal coefficients of the optical path were determined for CaYAlO4. dn/dT is negative at ∼1 μm, dno/dT=-7.8, and dne/dT=-8.7×10-6 K-1. Thermo-optic dispersion formulas were constructed. The obtained data are of key importance to the design of high-power mode-locked oscillators at ∼1 and ∼2 μm based on such laser hosts.

Refined Sellmeier and thermo-optic dispersion formulas for Li2B4O7

We report the high-accuracy Sellmeier and thermo-optic dispersion formulas for Li2B4O7, which provide an excellent reproduction of the temperature-dependent phase-matching conditions for second-harmonic generation (SHG) and sum-frequency generation (SFG) in the 0.2093–1.5352 µm range. In addition, Li2B4O7 was found to be nearly 90° phase-matchable for fifth-harmonic generation (5HG) of an Yb-doped fiber laser at 1.031 µm.

Sellmeier and thermo-optic dispersion formulas for CdGa2S4 and their application to the nonlinear optics of Hg1−xCdxGa2S4

This paper reports the Sellmeier and thermo-optic dispersion formulas for CdGa2S4 that provide excellent reproduction of the temperature-dependent phase-matching conditions in Hg0.35Cd0.65Ga2S4 and Hg0.51Cd0.49Ga2S4 for second-harmonic generation (SHG) and sum-frequency generation (SFG) in the 0.897–10.5910µm spectral range coupled with Sellmeier and thermo-optic dispersion formulas for HgGa2S4 presented in our previous papers (Kato et al., 2016 [1]; Umemura et al., 2012 [2]).

Thermo-optic dispersion formula for the ordinary wave in 5 mol% MgO doped LiNbO3 and its application to temperature insensitive second-harmonic generation

We report the high accuracy thermo-optic dispersion formula for the ordinary wave of 5mol% MgO doped congruent LiNbO3 (MgO:LiNbO3), which reproduces well our experimental data for the temperature-dependent birefringent phase-matching (BPM) and quasi-phase-matching (QPM) conditions with the oo–e, oo–o, and oe–o interactions in the 0.41–3.7μm range. In addition, we found the temperature insensitive quasi-phase-matched second-harmonic generation (QPM/SHG) points exist in periodically poled MgO:LiNbO3 (MgO:PPLN) with the oo–o and oe–o interactions for the first time.

Thermo-optic properties of Yb:Lu2O3 single crystals

A detailed study of thermo-optic properties of 1.5 at.% Yb:Lu2O3 single crystal is performed. Thermo-optic dispersion formulas are derived for dn/dT coefficient and thermal coefficient of the optical path. At the wavelength of 1.03 μm, dn/dT = 5.8 × 10−6 K−1. High-precision temperature-dependent measurements of the thermal expansion coefficient α are performed. At the room temperature (RT), α = 5.880 ± 0.014 × 10−6 K−1. Temperature dependence of the bandgap is analyzed, yielding RT value of E g = 5.15 eV and dE g/dT = –3.7 × 10−4 eV/K. Sensitivity factor of the thermal lens is calculated for a diode-pumped Yb:Lu2O3 crystal versus the pump spot radius and crystal temperature.