A passively Q-switched YVO4 Raman laser with orthogonally polarized emission at 1175.4 nm and 1165.2 nm

We originally proposed a method for obtaining an orthogonally polarized dual-wavelength Raman laser via a polarized-dependent effect of Raman shifting. Pumping a-cut YVO4 crystal with a passively Q-switched Nd: YAG laser, the system not only emitted a conventional Raman emission at 1175.4 nm but also a Raman emission at 1165.2 nm, which originated from the Raman shifts of 890 cm(-1) and 816 cm(-1), respectively. The polarization directions of the emissions at 1175.4 nm and 1165.2 nm were found to be along the c-axis and b-axis of the YVO4 crystal respectively, which enabled the orthogonally polarized operation. With a type-II KTP crystal, their sum-frequency generation (SFG) was obtained for the first time, and this result proved that the pulse series of these two emissions were simultaneous.