Compact, passively Q-switched, all-solid-state master oscillator-power amplifier-optical parametric oscillator (MOPA-OPO) system pumped by a fiber-coupled diode laser generating high-brightness, tunable, ultraviolet radiation

Abstract

We report on a compact, tunable ultraviolet laser system that consists of an optical parametric oscillator (OPO) and a longitudinally diode-pumped Nd:YAG master oscillator-power amplifier (MOPA). The pump energy for the whole laser system is supplied via a single delivery fiber. Nanosecond pulses are produced by an oscillator that is passively Q-switched by a Cr(4+):YAG crystal. The OPO is pumped by the second harmonic of the Nd:YAG MOPA. Continuously tunable radiation is generated by an intracavity sum-frequency mixing process within the OPO in the range of 245-260 nm with high beam quality. Maximum pulse energies of 1.2 mJ were achieved, which correspond to an optical efficiency of 3.75%, relating to the pulse energy of the MOPA at 1064 nm.

Kilowatt high average power narrow-linewidth nanosecond all-fiber laser

“…For nonlinear frequency conversion applications such as the optical parametric oscillator (OPO) [10,11] and second-harmonic generation (SHG) [5,6] , narrow-linewidth pulses can offer high conversion efficiency. Narrow-linewidth lasers are also desirable for coherent beam combinations, which are a promising way to scale the overall output power while maintaining the beam quality [12][13][14][15] .…”

“…High power narrow-linewidth nanosecond lasers have attracted much attention for a range of applications such as LIDAR [1–3] , nonlinear frequency conversion [4–6] , and coherent beam combinations [7–9] . For nonlinear frequency conversion applications such as the optical parametric oscillator (OPO) [10, 11] and second-harmonic generation (SHG) [5, 6] , narrow-linewidth pulses can offer high conversion efficiency. Narrow-linewidth lasers are also desirable for coherent beam combinations, which are a promising way to scale the overall output power while maintaining the beam quality [12–15] .…”

Tunable upconverted optical parametric oscillator with intracavity adiabatic sum-frequency generation

“…Optical parametric oscillators (OPOs) are very efficient devices for generating tunable downconverted light from a fixed-frequency pump. As for the upconversion, several schemes have been suggested [1][2][3][4][5][6][7][8][9] for the upconversion of the signal of an OPO, thus taking advantage of the wide tunability of this device for the sake of generating a frequency higher than the pump frequency. The upconversion process, be it a second-harmonic generation or a sumfrequency generation (SFG), faces the problem of small acceptance bandwidths, resulting from the higher dispersion of nonlinear crystals at short wavelengths.…”

“…The upconversion process, be it a second-harmonic generation or a sumfrequency generation (SFG), faces the problem of small acceptance bandwidths, resulting from the higher dispersion of nonlinear crystals at short wavelengths. In order to circumvent this issue, past suggestions required mechanical tuning [2][3][4][5][6], a tunable pump source [7,8], or using high-order processes with low efficiencies [9].…”

“…Tunable pump upconversion into a wavelength range of 6.22 nm in the red wavelength band with efficiencies of up to 4.7% has been obtained. This scheme has the advantages of simplicity, compactness, and robustness over previous configurations [2][3][4][5][6][7][8][9], while maintaining a high conversion efficiency and a wide tuning range.…”