We propose an experimental technique for efficient 2-µm light generation based on the intracavity noncritical phase matching optical parametric oscillator (OPO). Intra-cavity pumped by a diode pumped actively Q-switched Nd:YVO 4 laser operating at 1.3 µm, we have achieved efficient 2093-nm signal beam emission making full use of noncritical phase matching KTA-OPO. At a diode pump power of 9.8 W and a Q-switching repetition rate of 30 kHz, a signal beam with a spectral linewidth of ∼1 nm and an average power of 1.01 W have been obtained, giving a diode pump power to signal power conversion efficiency of 10.3%. The short pulse width of ∼3.4 ns is achieved, which is much shorter than other approaches with Q-switched operation to generate 2-µm laser beams.Index Terms-2 µm laser, noncritical phase matching, KTA crystal, optical parametric oscillator (OPO).

We report a continuous-wave (CW) KTA (KTiOAsO 4 )-OPO (optical parametric oscillator) with a compact linear cavity utilizing an LD pumped mixed crystal Nd:Lu 0.5 Y 0.5 VO 4 laser as the pump source for the first time. A singly resonant oscillator with low signal light loss was designed to reduce the OPO's threshold. Maximum output powers of 630 mW at 3475 nm and 190 mW at 1536 nm were obtained at a pump power of 13.2 W. A total conversion efficiency of 6.2% was achieved with respect to the incident diode pump power. The performance of this work demonstrates that a CW KTA-OPO derived by an LD pumped Nd 3+ doped solid laser can also produce efficient mid-infrared light.