The Research Of Raman Laser In Part Of Vanadate And KGW Crystals

Generally, there are two methods to investigate new wavelength of light: one is research in new laser materials;the other is convert the frequency of laser in nonlinear crystals, the approach of convert frequency usually are SHG,SFG,DFG and SRS. After the appearance of laser, the research of SRS (Stimulate Raman Scattering) is more and more maturation and varity of Raman lasers are occurred. Raman light is better than basic laser in high beam quality and narrow pulse, and without phase-matching. Some gas, liquid and solid Raman materials are the core of Raman laser. With the advantage of high ion density, good thermal and small-volume in solid materials, all–solid Raman laser is appreciated since 1980s. Now for high Raman shift and good transfer frequency, vanadate and tungstate crystals make good use in solid Raman laser.In this paper, Nd:YVO₄, Nd:GdVO₄,Nd:KGW, Yb:KGW crystals were used as Raman medium, and made a systemic research on the characteristics of the Raman lasers. The main content of this paper were follows:1,Diode-pumped, the first Stokes Raman laser at 1174 nm in a-cut Nd:YVO₄ crystal was demonstrated. The repetition rate of 19 kHz was obtained in Self-Raman crystal Nd:YVO₄ under intracavity actively Q-switched. With this repetition rate, the average output power of 197 mW and the pulse width of 26 ns were obtained under the laser diode pump power of 4 W; the corresponding slope efficiency was 15.6%. The pulse energy and peak-peak power were 10.4μJ and 397.5 W.2,The first Stokes Raman laser at 1174 nm in a-cut Nd:GdVO₄ crystal was also demonstrated. The repetition rate of 18 kHz was obtained in Self-Raman crystal Nd:GdVO₄ under intracavity actively Q-switched. Under this repetition rate, the average output power of 423 mW and the pulse width of 28.1 ns were obtained under the laser diode pump power of 3.5 W; the corresponding slope efficiency was 25%. The pulse energy and peak-peak power were 23.5μJ and 836 W.3,The operation of an all solid-state pulsed Nd:KGW Raman laser in different SRS vibration modes pumped by actively Q-switched Nd:YVO₄ laser was demonstrated. When the SRS vibration mode was P[gg]P, the Raman shift of 768 cm^-1 was operation, the first-Stokes laser was 1160 nm. The repetition rate of 18 kHz was obtained in Nd:KGW crystal. The pulse width of 31 ns and the average output power of 321 mW were obtained under the pump power of 4.3 W; the corresponding slope efficiency from diode light to Raman laser and pulse energy were 33.9% and 17.8μJ. When the SRS vibration mode was P[mm]P, the Raman shift of 901 cm^-1 was operation, the Raman laser was 1178 nm. The pulse width of 24.9 ns and the average output power of 342 mW were obtained under the pump power of 4.8 W. The corresponding slope efficiency and pulse energy were 28.2% and 19μJ.4,The operation of an all solid-state pulsed Nd:KGW Raman laser pumped by passively Q-switched Nd:YAG/Cr:YAG laser was demonstrated. The first-Stokes radiation of stimulated Nd:KGW Raman scattering at 1178 nm was generated. With different output couplers, the average output power of 336 mW at Stokes wavelength was obtained under the laser diode pump power of 5.74 W. The corresponding optical efficiency from the diode light to the Raman output was 9.85%. The pulse width of 1.65 ns and a pulse repetition rate of 10 kHz were also obtained.5,In this chapter, diode-pumped, Yb:KGW intracavity Raman laser at 1152 nm with V³⁺:YAG as saturable absorber was demonstrated. The average output power of 229 mW was obtained under the pump power of 9.68 W; the corresponding slope efficiency was 5.9%. The pulse width of 4.6 ns and the repetition rate of 13.4 kHz were also obtained.