Narrow-linewidth BaGa4Se7 optical parametric oscillator

Abstract

The linewidth of the BaGa 4 Se 7 (BGSe) optical parametric oscillator (OPO) was narrowed for the first time, to the best of our knowledge, by inserting a Fabry-Perot (FP) etalon into an L-shaped cavity. When a 15 mm long BGSe (56.3°, 0°) was pumped by a 1064 nm laser, the peak wavelength was ∼3529 nm, and the linewidth was 4.53 nm (3.64 cm −1 ) under type I phase matching. After inserting a 350 μm thick FP etalon, the linewidth was decreased to 1.27-2.05 nm. When the tilt angle of the etalon was 2.34°, the linewidth was 2.05 nm (1.65 cm −1 ), and the peak wavelength was still ∼3529 nm. When the tilt angle of the etalon was 3.90°, the peak wavelength was 3534.9 nm, and the linewidth was 1.27 nm (1.02 cm −1 ), which was the narrowest linewidth of a BGSe OPO, to the best of our knowledge. The beam quality was also improved after inserting the FP etalon.

Widely tunable and high resolution mid-infrared laser based on BaGa4Se7 optical parametric oscillator

“…When the center wavelength of the output laser was at 3.5 μm, its output spectral width was about 4.5 nm, which was slightly higher than that of KTA OPO, but much smaller than that of ZGP OPO. When we used the method of inserting an FP etalon into the L-type OPO cavity to narrow the spectral width of the output of BGSe OPO, the narrowest linewidth of 1.27 nm could be obtained [ 18 ].…”

Dispersion‐Engineered Super‐Gain Parametric Amplification in Nanoscale Optical Cavities

“…Consequently, the roundtrip loss for OPAs was nonlinear. [18][19][20][21][22] To compensate for this strong roundtrip decay in pump-wave amplitude, optimizing the cavity buildup of the pump-wave amplitude via nonlinear constructive interference was essential. Based on Equation (2), Figure 2 illustrates the sensitivity of the OPA process to the pump-wave amplitude (V m À1 ) in a 700 nm long cavity, which has a round trip loss of 0.1%.…”