High-beam-quality 2.1  µm pumped mid-infrared type-II phase-matching BaGa₄Se₇ optical parametric oscillator with a ZnGeP₂ amplifier

Abstract

We firstly demonstrated a tunable 2.1 µm pumped mid-infrared type-II phase-matching B a G a 4 S e 7 (BGSe) optical parametric oscillator (OPO). A signal tuning range of 3.82–3.99 µm was achieved. With a signal light produced by the BGSe OPO serving as seed, the Z n G e P 2 (ZGP) optical parametric amplifier (OPA) was first introduced. A 4.35 W mid-infrared laser was obtained in the novel type-II BGSe OPO with a ZGP OPA system, which was pumped by a 24 W 1 kHz Q -switched Ho:YAG laser. The beam quality factor M 2 of the whole system is ∼ 2.3 , which is over a 50% promotion on the previous M 2 results of single BGSe OPO.

High Repetition Rate, Tunable Mid-Infrared BaGa4Se7 Optical Parametric Oscillator Pumped by a 1 μm Nd:YAG Laser

“…The Gaussian fitted curve has a full width at half maxima (FWHM) of 0.49 nm with a central wavelength of 1442.42 nm. According to the phase-match condition, the FWHM of generated mid-infrared is estimated to be 3.92 nm at 4061 nm, much narrower than the 2 µm pumped degenerate parametric conversion [21].…”

“…The maximum energy of 21.5 mJ/pulse has been reported using a large-size BGSe of 10 × 10 × 16 mm 3 [17]. However, due to the relatively low thermal conductivity [18] and the increasing damage probability under high repetition rate laser pumping [19][20][21], reports on the high average power BGSe-OPO pumped with 1064 nm laser are rare.…”

Narrow-linewidth BaGa4Se7 optical parametric oscillator

“…With a signal wave produced by the BGSe OPO serving as seed, the ZnGeP 2 (ZGP) OPA was demonstrated in 2020. The corresponding bandwidth (FWHM) of the signal and idler was approximately 8 and 7 nm with a peak wavelength of 3.95 and 4.44 μm, respectively [12] . In 2020, Zhang et al [13] reported a high-energy, narrow spectral linewidth MIR laser from a Nd:YAG pumped BGSe OPO.…”

Ho:YAG laser at 2097 nm pumped by a narrow linewidth tunable 1.91 μm laser

“…The output power of the Ho:YAG laser is between 21.04 and 23.53 W and the slope efficiency is between 64.08 and 68.26% at the pump power of 39.8 W. The output power and slope efficiency corresponding to the pump wavelength of 1907.36 nm are 23.53 W and 68.26%, respectively. This study illustrates that fine-tuning the pump wavelength is an effective way to improve the slope efficiency and output power of the Ho:YAG laser at room temperature.A 2.1 μm laser is located in the atmospheric window and widely used in applications such as laser medical 1 , material processing 2 , optical communication lidar detection and ranging systems 3 , and the optical parametric oscillators 4,5 . At present, the main approach to obtain lasers with wavelengths at 2.1 μm is to pump a Ho-doped crystal with a 1.9 μm laser that coincides with the absorption wavelength peak of Ho-doped crystal.…”

“…A 2.1 μm laser is located in the atmospheric window and widely used in applications such as laser medical 1 , material processing 2 , optical communication lidar detection and ranging systems 3 , and the optical parametric oscillators 4,5 . At present, the main approach to obtain lasers with wavelengths at 2.1 μm is to pump a Ho-doped crystal with a 1.9 μm laser that coincides with the absorption wavelength peak of Ho-doped crystal.…”