Cr (4 +): Mg <sub> 2 </ Sub> Sio <sub> 4 </ Sub> As A Laser Gain Medium And Saturable Absorber

The development of the Cr⁴⁺–doped crystals and successful working of pertinent lasers extend the tune of solid tunable lasers from 0.7μm～1.0μm generated by Cr³⁺ and Ti³⁺ ions to 1.0μm～1.8μm ,so the study of them has become the hot pot of the study of solid tunable lasers. Especially the Cr⁴⁺:Mg₂SiO₄ crystal will hopefully become the ideal medium of solid tunable lasers in the near infrared wavelength, in addition, the second-harmonic red laser generated by Cr⁴⁺:Mg₂SiO₄ laser can conquer the shortcoming of diode laser, and Cr⁴⁺ ion was found that it has the characteristic of saturated absorption at 0.9μm～1.2μm ,so the study of it will be the most important.In this thesis, we used the Q-switched Nd:YAG laser pulse focused by lens to pump the Cr⁴⁺:Mg₂SiO₄ crystal, with the pump laser pulse duration and energy of 30ns and 50 mJ separately, and got the laser pulse with center wavelength, pulse duration and energy of 1.22μm , 8.2 ns and 10 mJ on the best work condition. On the base of Zhangguowei′s approximation about gain-switching and the parameter of Cr⁴⁺:Mg₂SiO₄ crystal, we calculated the time characteristics of Cr⁴⁺:Mg₂SiO₄ laser pulse with rate equation by numerical method, obtained the conclusion that the laser pulse duration is only related to the pump energy and cavity length: the larger the pump energy is, the narrower the pulse duration is; the longer the cavity is, the wider the...