TY - JOUR

T1 - An optical parametric oscillator based on BaGa2GeS6 with energy exceeding 2 mJ at 6.45 μm

AU - Erushin, E. Yu

AU - Sere, S. E.

AU - Vostrikova, M. V.

AU - Boyko, A. A.

AU - Shevyrdyaeva, G. S.

AU - Badikov, D. V.

AU - Karapuzikov, A. A.

AU - Kostyukova, N. Yu

N1 - The OPO development was supported by the State Assignment of ILP SB RAS FWGU - 2021–0010. The refined Sellmeier coefficients were determined with the financial support of the Ministry of Education and Science of the Russian Federation (Project No. FSUS-2025–0011).

PY - 2026/3

Y1 - 2026/3

N2 - A high-energy optical parametric oscillator (OPO) based on a BaGa2GeS6 (BGGS) nonlinear crystal pumped by a home-built Q-switched Nd:YAG laser operating at 1064 nm with 15 ns pulse duration and 10 Hz repetition rate was demonstrated and characterized. The system generated idler radiation near 6.45 μm with a maximum pump-to-idler conversion efficiency of 2.23 % at a pump energy of 92 mJ, corresponding to an idler output energy of 2.06 mJ. Over an hour monitoring period, the output energy stability was 1.9 % RMS, and the average beam quality factor was M2 was determined to be 33 at a pump energy of 85 mJ. The phase-matching characteristics were experimentally studied via angular tuning of the BGGS crystal, and refined Sellmeier coefficients for the ordinary and extraordinary refractive indices were obtained using a least-squares fit, reducing the error between theory and experiment to 0.1°. The idler spectral linewidth, estimated by convolution of the measured pump and signal spectra, was 63.5 nm. The findings suggest that the BGGS crystal represents a promising nonlinear optical material for the generation of high-energy radiation within the mid-infrared spectral range.

AB - A high-energy optical parametric oscillator (OPO) based on a BaGa2GeS6 (BGGS) nonlinear crystal pumped by a home-built Q-switched Nd:YAG laser operating at 1064 nm with 15 ns pulse duration and 10 Hz repetition rate was demonstrated and characterized. The system generated idler radiation near 6.45 μm with a maximum pump-to-idler conversion efficiency of 2.23 % at a pump energy of 92 mJ, corresponding to an idler output energy of 2.06 mJ. Over an hour monitoring period, the output energy stability was 1.9 % RMS, and the average beam quality factor was M2 was determined to be 33 at a pump energy of 85 mJ. The phase-matching characteristics were experimentally studied via angular tuning of the BGGS crystal, and refined Sellmeier coefficients for the ordinary and extraordinary refractive indices were obtained using a least-squares fit, reducing the error between theory and experiment to 0.1°. The idler spectral linewidth, estimated by convolution of the measured pump and signal spectra, was 63.5 nm. The findings suggest that the BGGS crystal represents a promising nonlinear optical material for the generation of high-energy radiation within the mid-infrared spectral range.

UR - https://www.scopus.com/pages/publications/105027275757

UR - https://www.mendeley.com/catalogue/e2a502aa-172b-38d0-8bdd-2ad314b3df90/

U2 - 10.1016/j.infrared.2026.106393

DO - 10.1016/j.infrared.2026.106393

M3 - Article

VL - 154

JO - Infrared Physics and Technology

JF - Infrared Physics and Technology

SN - 1350-4495

M1 - 106393

ER -