Non-critical phase-matched 1.47  µm nanosecond optical parametric oscillator pumped at 1030  nm

A high-energy nanosecond optical parametric oscillator (OPO) operating at 1.47 µm under non-critical phase-matching (NCPM) conditions is demonstrated using a 1030 nm pump. Using a KTA-based OPO pumped by a single-frequency 1030 nm nanosecond laser at a repetition rate of 500 Hz, a maximum signal pulse energy of 6.6 mJ at 1.47 µm was achieved, accompanied by an idler output of 1.6 mJ at 3.4 µm, corresponding to a total parametric conversion efficiency of 39%. To verify the general applicability of the 1030 nm-pumped NCPM scheme, the output characteristics of a KTP-OPO are also investigated under identical pumping conditions. This OPO scheme avoids the limitations of critical phase matching (CPM) OPO configuration when generating nanosecond laser at 1.47 µm.