Tunable Stokes laser generation based on the stimulated polariton scattering in KTiOPO₄ crystal.

The tunable Stokes laser characteristics based on the stimulated polariton scattering in KTiOPO4 (KTP) crystal and the intracavity frequency doubling properties for the Stokes laser are investigated for the first time. When the pumping laser wavelength is 1064.2 nm, and the angle between the pumping and Stokes beams outside the KTP crystal changes from 1.875° to 6.750°, the obtained tunable Stokes laser wavelength varies discontinuously from 1076.5 nm to 1091.4 nm with four gaps. When the pumping pulse energy is 120.0 mJ, the maximum Stokes pulse energy is 46.5 mJ obtained at the wavelength of 1086.6 nm. By inserting a LiB3O5 (LBO) crystal into the cavity, the obtained frequency-doubled laser wavelength is inconsecutive tunable from 538.5 nm to 543.8 nm. The maximum frequency-doubled laser pulse energy is 15.9 mJ at the wavelength of 543.5 nm.