Compact Passively Q-Switched Rbtiopo4 Cascaded Raman Operation

Compact passively Q-switched RbTiOPO4 cascaded Raman laser operation has been investigated for the first time, to our knowledge. A Nd:YAG/Cr4+:YAG composite crystal was adopted for passively Q-switched fundamental laser generation. 440 mW multi-Stokes laser output with X(ZZ)X configuration according to the Porto notations was achieved under the incident pump power of 10 W. The measured spectra contained three wavelengths of 1149, 1165, and 1185 nm based on the Raman shift of 271 and 687 cm(-1). Different from actively Q-switch cascaded Raman laser with Stokes wave from low order to high order oscillating in sequence, three intensity lines were output for the whole experiment in this passively Q-switched multi-Stokes laser. The output spectra could be varied and optimized based on the output coupler coating design. Output spectra not sensitive to incident pump power for passively Q-switched cascaded Raman laser have advantages in multiwavelength laser applications. (C) 2018 Optical Society of America