Adhesive-free bond quasi-noncritical phase-matched and quasi-phase-matched optical parametric oscillations

Abstract

With adhesive-free bond (AFB) technology, two walk-off compensated (WOC) KTP composites that consist of 16 layers of 2-mm thick single KTP crystals in each have been designed and prepared for 1.064-μm pumped 2-μm OPO's by means of quasi-noncritical phase-matching (QNCPM) and quasi-phase-matching (QPM). Output pulse energies of 49 μJ and 35 μJ have been achieved for QNCPM and OPM OPO's at pump energy of 523 μJ with pulse duration of 15 ns and repetition rate of 1 KHz, respectively. The OPO pump thresholds were measured as low as 254 μJ (44.6 MW/cm 2 ) for the both types of OPO's. The wavelength shifts were measured to be around 11 nm for both the signal and idler beams when KTP temperature was raised from room temperature to 220°C.