Ho:YAG laser pumped walk-off compensated mid-infrared ZGP optical parametric oscillation

Abstract

We have demonstrated a novel folded linear resonator for walk-off compensated (WOC) optical parametric oscillation (OPO) in a single ZGP crystal. The OPO uses the doubled ZGP crystal length in a WOC configuration while simplifying requirements on crystal alignment. With a Q-switched Ho:YAG laser as a pump source, a maximum output power of 2 W at a wavelength of 4.72 μm has been measured for a pump power of 11.9 W in a 15-mm long type-I phase-matched ZGP crystal. The measured OPO quantum slope efficiency is above 50%.

Output characteristics of a singly-resonant optical parametric oscillator: Dependence on the variation of the signal and idler output coupling

“…In this way, a power conversion efficiency as high as 10-20% for generation of infrared radiation was achieved with an average power of more than 5 W. 6,[10][11][12][13][14][15][16][17][18] For output radiation in the 2.2-4 µm region (corresponding to idler when SRO is pumped by 1.064 µm-Nd : YAGlaser), in most researches infrared radiation at the idler wavelength was obtained by using SRO S with an output coupler of high reflectivity at the signal wave. 6,10,12,[15][16][17][18] On the other hand, Peng et al also obtained infrared radiation of wavelength 3.84 µm with a high conversion efficiency of 16% by using SRO I. 14 Therefore, it is worthwhile to carry out a comparative study of output characteristics of SRO S and those of SRO I under the same parameters of SRO such as pump laser, crystal and the wavelengths of signal (λ s ) and idler (λ i ) while varying the reflectivity of the output coupler.…”