Properties of Nd~(3+)-doped and undoped tetragonal PbWO_(4), NaY(WO_(4))_(2), CaWO_(4), and undoped monoclinic ZnWO_(4) and CdWO_(4) as laser-active and stimulated Raman scattering-active crystals

摘要

Spectroscopic, laser, and x~(3) nonlinear optical properties of tetragonal PbWO_(4), NaY(WO_(4))_(2), CaWO_(4), and monoclinic CdWO_(4) and ZnWO_(4) were investigated. Particular attention was paid to Nd~(3+) -doped and undoped PbWO_(4) and NaY(WO_(4))_(2) crystals. Their absorption and luminescence intensity characteristics, including the peak cross sections of induced transitions, were determined. Pulsed and continuous-wave lasing in the two~(4)F_(3/2) →~(4)I_(11/2) and ~(4)F_(3/2) →~(4)I_(13/2) channels was excited. For these five tungstates, highly efficient (greater than 50%) multiple Stokes generation and anti-Stokes picosecond generation were achieved. All the observed scattered laser components were identified. These results were analyzed and compared with spectroscopic data from spontaneous Raman scattering. A new crystalline Raman laser based on PbWO_(4) was developed for the x~(3) conversion frequency of 1-μm pump radiation to the first Stokes emission with efficiency up to 40%. We classify all the tungstates as promising media for lasers and neodymium-doped crystals for self-stimulated Raman scattering lasers.