A 2.048μm Tm,Ho:GdVO₄ Laser Pumped Doubly Resonant Optical Parametric Oscillator Based on Periodically Poled Lithium LiNbO₃

A multi-grating periodically poled LiNbO₃ (PPLN) doubly resonant optical parametric oscillator (DROPO) pumped by a 2μm laser is demonstrated experimentally. Employing acousto-optically Q-switched Tm,Ho:GdVO₄ laser with pump pulse of 25ns and repetition rate of 10kHz as pump sources firstly, the noncritically quasi-phase-matched (QPM) tunable mid-IR output in 3.87--4.43μm is produced. Wavelength tuning is achieved with crystal temperature tuning from 50--180°C. When the incident average pump power is 3W at
2.048μm, the total OPO output power of 195mW at wavelength 3.88μm is obtained, corresponding to optical-to-optical conversion efficiency up to 6.5%.