Dual-wavelength eye-safe optical parametric oscillator intracavity driven by a coaxially end pumped laser

A compact and flexible dual-wavelength eye-safe intracavity optical parametric oscillator (IOPO) configuration driven by a coaxially end pumped laser was proposed. Two fundamental waves were provided by a coaxially end pumped Qswitched dual-wavelength laser with combined two laser crystals, and the OPO cavity was placed inside the laser cavity for efficient conversion. Theoretical simulations showed that the power ratio for each signal wave, as well as the time interval between two pulses at different wavelengths, were both tunable by tuning the pump focusing depth or pump wavelength. Experimental results were performed with combined laser crystals (Nd:YAG and a-cut Nd:YLF) and a nonlinear crystal (KTA), demonstrating coincident conclusions. The maximum OPO output power was 724 mW (388 mW at 1506 nm and 336 mW at 1535 nm) with the LD pump power of 10 W at 6 kHz, corresponding to the opticaloptical conversion efficiency of 7.24%. As there was no gain competition between two fundamental waves, stable signal output could be obtained. Moreover, various wavelength pairs can be generated by using different laser crystal combinations. It is believed that this is a promising method for simultaneously generating dual-wavelength eye-safe lasers pulses.