Narrowband intracavity MgO:PPLN optical parametric oscillator near degeneracy with a volume Bragg grating

• A narrow-bandwidth near-degenerate singly resonant MgO:PPLN OPO is proposed.
• VBG is used out of the pump cavity for a stable operation and narrowing linewidth.
• 1.064 μm and 2.1 μm lasers with high power are obtained at the same time.
• We achieve 2.1 μm laser with high power, narrowband and good beam quality.

We report a narrow-bandwidth near-degenerate MgO:PPLN optical parametric oscillator (OPO) based on a volume Bragg grating (VBG) output coupler (OC) intracavity pumped by a linearly polarized Q-switched Nd:YAG laser. Maximum 2.1 μm output power of 7.1 W with beam quality factor M2 of 2.0 and 2.3 in horizontal and vertical directions is achieved. 23.5 W of 1 μm radiation with fundamental mode is obtained simultaneously.