Internal Q-switching and self-optical parametric oscillation in a two-dimensional periodically poled Nd:MgO:LiNbO_3 laser

We report on an internally Q-switched self-optical parametric oscillator (SOPO) based on a monolithic two-dimensional (2D) periodically poled Nd:MgO:LiNbO(3) (Nd:MgO:PPLN) integrating three device functionalities of a laser gain medium, an electro-optic Bragg Q-switch, and an optical parametric gain medium (OPGM). The quasi-phase-matching conditions required by the Bragg Q-switch and OPGM are both satisfied in the 2D nonlinear photonic crystal (NPC) structure formed in the Nd:MgO:PPLN. A 1525 nm signal with a pulse energy of ∼3.3 μJ (>350 W peak power) was obtained from the SOPO at 8.5 W diode pump power. An off-angle signal at 1612 nm, amplified by a unique gain-enhancement effect in this 2D NPC, was also observed. Tuning of the SOPO in the eye-safe region was demonstrated.