Continuous-wave, singly resonant OPO at 3 \mu m

TL;DR

This paper demonstrates a continuous-wave singly resonant optical parametric oscillator at 3.3 micrometers using MgO:PPLN and a Yb-fiber laser, achieving high power and narrow linewidth with observed thermal effects.

Contribution

It presents the first continuous-wave SRO at 3.3 micrometers with high power, narrow linewidth, and analysis of thermal effects and pump depletion phenomena.

Findings

Generated 0.2 W at 3.3 μm with 25 W pump power.

Achieved single-longitudinal-mode output with ~5 MHz linewidth.

Observed thermally induced optical bistability and spectral hole burning.

Abstract

We report a continuous-wave, singly resonant optical parametric oscillator (SRO) at 3.3 \mu m by using a MgO:PPLN crystal as the gain medium and a Yb-fiber laser at 1.064 \mu m as the pump source. At 25-W pump power, the SRO generated 7.4 and 0.2-W powers at 1.57 and 3.3 \mu m, respectively. The 3.3-\mu m SRO has a single-longitudinal-mode output with a ~5-MHz linewidth. We observed thermally induced optical bistability in the SRO due to the slight absorption of the 3.3-\mu m wave in the MgO:PPLN crystal. Pump depletion was clamped at 60% while spectral hole burning was observed in the depleted pump.