Cascaded OPO based on single KTA crystal for 2.6 μm laser generation

Cascaded OPO based on single non-critical phase matching KTA crystal was proposed. The fundamental oscillation at 1.06 m was achieved by LD end-pumped Nd: YVO4 crystal laser, then the non-critical phase matching cut KTA crystal was intra-cavity pumped. The 1.53 m signal light produced by KTA-OPO was confined in the OPO cavity to realize the second OPO conversion in the same KTA crystal. Under 8 W incident diode pump power at 808 nm, a power exceeding 400 mW and slope efficiency of 12.7% at 2.6 m were achieved based on cascaded OPO. Results show that the cascaded KTA-OPO is an efficient way to achieve 2.5-2.7 m pulsed laser.