2637.5 nm Mid-infrared SrWO₄ Raman laser intracavity-pumped by an actively Q-switched Ho:YAG laser

We first report a 2.6 mu m mid-infrared SrWO4 Raman laser, intracavity-pumped by an actively Q-switched Ho:YAG laser. The 2122 nm fundamental laser was generated from the Ho:YAG laser, which was resonantly pumped by a 1908 nm continuous wave Tm:YLF laser. Based on the stimulated Raman scattering effect of SrWO4 crystal, the fundamental wavelength of 2122 nm was converted into the Raman wavelength of 2637.5 nm, corresponding to the Raman shift of 921 cm(-1). The output characteristics of SrWO4 Raman laser were investigated at various repetition frequencies. The maximum average output power was 720 mW at the 6.6 W absorbed pump power and 4 kHz repetition frequency. The maximum single pulse energy and peak power were 196 mu J and 10.9 kW at the 5.6 W absorbed pump power and 3 kHz repetition frequency, respectively. The pulse Raman laser near 2.6 mu m has potential applications in material processing, spectroscopy, remote sensing, and nonlinear frequency conversion.