YVO4 cascaded Raman laser for five-visible-wavelength switchable emission.

ABSTRACT

We report switchable emission of visible light at five wavelengths generated in a $\text{YVO}_4$YVO4 cascaded Raman cavity driven by an acousto-optic ${Q}$Q-switched NdYAP laser at 1080 nm. The second-harmonic generation and sum-frequency generation of the fundamental, first-Stokes, and second-Stokes waves were realized based on the angle-tuned BBO crystal. The phase-match angle tuning span of a BBO crystal is only approximately 2.3° to allow the frequency mixing to produce five visible wavelengths on demand. At an absorbed pump power of 5.96 W and a pulse repetition frequency of 10 kHz, average output powers of 800, 340, 460, 190, and 326 mW were obtained for 539.9, 567.2, 597.4, 631.0, and 668.5 nm lasers, respectively. The results show that the cascaded Raman laser system with an angle-tuned BBO crystal can provide a convenient and efficient method to achieve wavelength-switchable visible emission for multi-wavelength laser applications.