| In recent years, the rapid development of laser technology plays a huge role in the defense, medical, information and measurement, medical, defense, scientific research, industry and agriculture. Laser crystal is the main constituent of laser, it determines the quality of the laser directly, which is the foundation for the development of the laser. Therefore, Laser crystal got the attention of researchers both at home and abroadt. Since1961, Johnson and Nassu developed the first continuous laser successfully, laser crystal research began to rapid development. In1962, pulse ruby laser was developed, in1963, Ni2+:MgF2crystal laser was finished, which realized solid-state tunable laser operation under the condition of low temperature. Throughout the70s, scientists spent more energy in the study of laser crystal, discovered the neodymium-doped yttrium aluminum garnet(Nd3+:YAG) and Chrysoberyl(Cr3+:BOAl2O4)), Chrysoberylas working substance, wonthe solid-state tunable laser operation for the first time, marked as the industrialization of laser crystal has been preliminary implementation. In the80s, Titanium Doped Sapphire Crystal (Ti:Al2O3) was discovered, made the generation of laser time shorter, even achieved femtosecond magnitude, laser technology is play a role in the field of other school gradually. In the90s, the world go into the era of solid-state laser fully with the Neodymium-Doped Yttrium Alum Acid Crystal (Nd3+:YVO4).In recent years, Nd3+ions is widely used in laser crystal with its rich energy level, the larger absorption and emission cross section. Among them, the Nd:LuVO4has received extensive attention of people once reported. Nd:LuVO4crystals have high thermal conductivity, are more likely to get high efficiency with excellent level lifetime, the larger absorption and emission cross section, the absorption of larger bandwidth, In addition. Nd:LuVO4crystals also have excellent polarization characteristics and high conversion efficiency. In this paper, we study the structure, spectroscopy, laser output characteristics of Nd:LuVO4crystal growth of the pulling method. The main contents are as follows:(1) It introduces the origin and development of solid-state laser of semiconductor pump, compared with the traditional lasers, it has highlight the advantages of semiconductor solid-state lasers. In addition, I summarized the research status of LUVO4crystal at home and abroad, and predicted the development trend of the future.(2) I analysis the lattice vibration spectrum of Nd:LuVO4crystals. Nd:LuVO4crystals is a part of the zircon crystals, his original cell contains two molecular formula, a total of36basic lattice vibration mode. This chapter firstly introduces related theory knowledge:normal coordinates, from the perspective of the theory, tells the normal coordinates of Nd:LuVO4crystals. Under the normal coordinates, I analyzed the space group of crystal, and finally get the formula:ζ=5A1g+7B1g+2B2u+2B2g+10Eg. we proved theoretically that34Raman active optical mode only can be observed in experiment. Then, several explanations of Raman scattering is introduced: the classical theory and quantum theory, resonance Raman and electronic Raman, etc. I explained the general selection rule of infrared absorption and crystal follow under the symmetry of selection rule.(3) I analysis the basic theory of Raman scattering from the theoretical, selected the A1g:X(ZZ)X. A1g+B1g:X(YY)X、B2g:Z(XY)Z、E1g:Y(XZ)Y four kinds of geometrical configuration, and then, measure the Nd:LuVO4crystal Raman spectra through the confocal micro Raman spectrometer. We believe that Nd:LuVO4crystal can be used as the matrix of Nd3+, because there is no obvious dislocation. This chapter measured Nd:LuVO4crystal absorption spectrum and fluorspar spectrum. And I calculate the spectral line intensity, and the variety of the absorb radiation integral emission cross section, level lifetime, fluorescent branching ratio and other important parameters by J-O theory. (4) Simply, I introduced the semiconductor laser pumped solid state laser, and the working principle of the laser using indirect coupling method, which contains a lens system coupling, self-focusing lens coupling and fiber coupling, etc. Then, I deduced the threshold of laser output, light-light conversion efficiency and the efficiency of the inclined calculation formula from the theory. Using the knowledge, I designed a1.34μm continuous wave laser experiment device, and used this device, compared a-cut and c-cut Nd:LuVO4crystal output power. For1.34μm output light, the transmittance of phase a-cut crystal light-light conversion effect and efficiency is lower than c-cut one when the transmittances of output lens are same. For the same piece of crystal, the crystal light-light conversion efficiency was falling, when the transmittance of output lens was rising.(5) The basic properties of YAG crystal were introduced, I explained working principle of passively Q-switched and the mode-locking lasers; designed the1.34μm passively Q-switched and the mode-locking lasers, respectively by power meter and oscilloscope to record data, analysis of pulse width, repetition frequency, single pulse energy and peak power.(6) Finally, I summarize the full text, list the innovation points and need further research work. |
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