Observation of the effective linear polarization induced by the asymmetrical Raman gain of YVO4 crystal

• Effective linear polarization was demonstrated from asymmetrical Raman gain.
• Effective SRS conversion was achieved in a Z-shape cavity.
• A polarization extinction ratio of 10.4-dB was observed.
• The orthogonal polarization Raman laser source can be developed.

We originally present a linearly polarized Raman radiation emitted from an actively Q-switched Nd:YAG/YVO4 laser. An 1175.25 nm Raman output was achieved using a uniaxial a-cut YVO4 crystal in a Z-shape laser cavity. The stable Raman power of 1.8 W was obtained, corresponding conversion efficiency of 8.8% from 1064 nm to 1175 nm. The Raman radiation with a polarization extinction ratio of 10.4-dB was observed for the first time. Our experimental results demonstrate that the asymmetrical Raman crystal gain can result in a uniform linear polarization and permit emitting orthogonal polarization radiation in a cascaded Raman laser.