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The Laser Property Of New Solid-state Material By Q-switching Technology

Posted on:2015-11-14Degree:MasterType:Thesis
Country:ChinaCandidate:H Q LiFull Text:PDF
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The new laser material which has good optical properties and thermal shock re-sistance is the hot field in the laser research. We use the Q-switching technology, possessing high peak power and large energy, to understand the laser output charac-teristics of different wavelengths from the new laser material, and can have the benefit expanding the application of new laser material in solid-state laser field. Lithium tan-talite (LiTaO3) and Lutetium lithium fluoride (LuLiF4) are typical new laser material. LiTaO3crystal doped with rare-earth ions can generate laser oscillation, electro-optic effect and nonlinear optical frequency conversion just in one crystal. It has extensive application in solid-state laser field, nonlinear optics and integrated optics. Benefit-ting from matching in expansion coefficient and conductivity of LuLiF4along each the crystal axes, LuLiF4has reduced astigmatic thermal lensing effect and suitable for high power laser operation. Compared with oxides, fluoride crystals have high trans-parency in a wide range and low phonon-energy which reduces non-radiative relaxation between adjacent energy levels. These features make the LuLiF4has been important laser material in the field of solid-state laser.In the chapter one, we introduce the LiTaO3crystal and LuLiF4crystal, including physical, thermal and optical properties. In the second part of this chapter, we detailed describe their application situation and related research in solid-state laser. In the third part of this chapter, we introduce the principles of Q-switching techniques used in this dissertation. Furthermore, We focus on the laser application of LuLiF4in the range from2μm to300nm and rare earth-doped LiTaO3crystalsIn the chapter two, we study the growth of Nd,Mg:LiTaO3crystal with the highest Nd3+ions doping concentration, as well as the polarization process, absorption spec- trum and fluorescence emission spectrum of this crystal. In the continues-wave laser experiment, we obtain the laser output from Nd,Mg:LiTaO3, and discusses the different polarized pump light effect on the laser output. In the pulsed laser operation, we use an acousto-optic crystal in the cavity to Q-switch the Nd,Mg:LiTaO3, and obtain pulse peak power of kW level which is three orders of magnitude higher than that previously reported in Nd,:LiTaO3crystal. Focuses on the properties of Nd,Mg:LiTaO3crystals in the pulsed operation, and discuss the Nd,Mg:LiTaO3can self-repair the photorefractive effect for stable pulsed laser operation.In the chapter three, we introduce the theoretical analysis and numerical simula-tion of passively Q-switching for the preparation of Nd:LiLuF4dual-wavelength laser experiment. In this chapter, we use ZEMAX optical design software to optimize focus-ing optics of the pump light. By using generalized paraxial-wave resonator analysis, the stable cavity for both positive thermal lens and negative thermal lens is designed. In numerical simulation, by using fourth-order Runge-Kutta method, we solve the en-ergy levels coupled rate equations in the saturable absorber (V3+:YAG) passively Q-switched operation. Finally, we research on the factors which have influence on the laser energy and pulse prepetition rate, including pump power and doped vanadium ion (V3+) concentration. All of these factors have important guidance for the high energy pulsed laser experiments.In the chapter four, under the cavity which was designed in chapter three, we real-ize an efficient continuous-wave and passively Q-switched dual-wavelength Nd:LuLiF4laser at1314nm and1321nm for the first time. Its laser spectrum, output power, the mechanism of dual-wavelength and beam quality are also analyzed. By using a sat-urable absorber (V3+:YAG) with high V3+ions doping concentration, the passively Q-switched Nd:LuLiF4pulsed laser is successful obtained. The influence of different output coupler on the pulsed laser is studied, as well as dual-wavelength operation has an impact to saturable absorber. Maximum pulse energy extracted from the resonator is108.7μJ at17.2kHz pulse repetition rate, and maximum peak power is885W.
Keywords/Search Tags:rare earth doped solid-state laser, lutetium lithium fluoride crys-tals, lithium tantalite crystal, Q-technology, acousto-optic Q-switches, saturable-absorberQ-switch, Photorefractive effect, 1.3μm dual-wavelength laser
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