Compact efficient high-power continuous-wave Nd:YVO4/KGW/LBO Raman lasers for selectable wavelengths within 559-603 nm

Abstract

Compact efficient high-power continuous-wave Nd:YVO4 Raman lasers for selectable wavelengths within 559-603 nm are achieved by using KGW crystal for intracavity stimulated Raman scattering (SRS) and lithium triborate (LBO) crystal for intracavity sum frequency generation (SFG) and second harmonic generation (SHG). The LBO crystal with the cut angle in the XY plane for the type-I phase matching is used to perform intracavity SHG or SFG. Experimental results reveal that the participated Stokes lines include the internal vibration mode at 901 cm-1, the external vibrational mode at 209 cm-1, and the combination mode of the 901 cm-1 and 209 cm-1 Raman shifts. By tuning LBO temperature for attaining the maximum output power, the output spectrum reveals the triple peaks of 588.7, 595.7, and 603.1 nm with the intensity ratio of 10:4:1. Under this circumstance, the output power can reach the highest value of 10.8 W at a pump power of 40 W. Furthermore, the output spectrum can be simply concentrated on the single peaks among 588.7 (orange), 565.7 (yellow), and 559.1 nm (lime) by tuning LBO temperature to fulfill the selection of the critical phase matching. The output powers at a pump power of 40 W can be up to 8.0, 6.1, and 9.8 W for the single-peak emission at 588.7, 565.7, and 559.1 nm, respectively. Finally, a dual-peak emission of 565.7 and 572.3 nm with total output power of 5.2 W can be generated by tuning LBO temperature to match the SFG for 572.3 nm.