Study On Yb:YAG Laser Materials

Laser materials and components are the core and foundation of the development of laser technology, which has the significance of milestone. The first laser in the world was born in 1960. During half a century, laser technology has been developed rapidly, and has been widely applied in tactical laser weapon (hard and soft killing damage), laser guidance, laser range finder, laser communications, advanced manufacturing technology (laser processing and laser welding), laser medical treatment, laser display fields and so on, and entered the high-speed developing period. It will make the pillar industry of 21st century. All the main countries take it as an national strategy high technology development plan.At present, laser technology has developed towards the direction to one pump (LD), two high (high power, high energy) and three more (more miniaturing, more intelligent, more integrating), three super (super short, super fast, super strong). In addition, laser materials are the core and forerunner of the development of laser technology. Therefore, laser material has the large scale of applied market demand on laser and components in high-tech fields.Yb:YAG laser materials (crystal and ceramic) have excellent physical and optical properties. The absorption peak (941nm) is close to the emission peak (1030nm), and have low quantum defects and wide pumping absorption bands. Its electronic structure is simple, having not excited state absorption, upconversion or concentration quenching. Moreover, it has longer fluorescence life and higher energy than Nd:YAG. The percent heat Yb:YAG generates can be four times lower than that of, and Yb:YAG has the least heat effect of all the mediumms. It is proved that Yb:YAG laser matrix materials are superior to Nd:YAG in aspects of laser performance, reliability and cost, etc.In this paper, the crystal growth, ceramic preparation and performance of Yb:YAG were studied systematically.(1). The new technics that is filling protective atmosphere in the lower vacuum has been presented firstly. According to designing reasonable temperature field and selecting the optimum technical parameters, the Yb:YAG laser crystal with a dimension ofΦ20-35mm×60-100mm was grown by Czochralski method to medium frequency induction heating.(2). The performance of Yb:YAG crystal were investigated by using several measurements, such as XRD, TG-DTA, absorption spectrum, fluorescence spectrum and so on. Meanwhile, the defects of Yb:YAG crystal were analyzed and discussed systematically.(3). The one-time annealing process has been presented firstly, and the optimum annealing technical parameters can be obtained. In addition, the influence of one-time and second-time annealing process on crystal quality was studied.(4). The extinction ratio of Yb:YAG crystal with a dimension ofΦ3mm×10mm was studied, and the extinction ratio is equal to 48.6dB. The optical uniformity of laser components was tested, and the interference fringes less than or equal to 0.095 article per 25mm, which has reached the international advanced level.(5). Using 3mm×8mm×1mmYb:YAG laser micro-chip, respectively, the use of green light and yellow light output mirror appearance to achieve room temperature operation of 1030nm wavelength, results show that the laser performance is better when the yellow light output mirror was used. The pumping power is 2W, the threshold power is 189 mW, the output power is up to 152.5mW, The real output power is equal to 213.5mW. Light-light conversion efficiency and slope efficiency is 11.79%,11.87%, respectively.(6). Using 2mm×2mm×10mmYb:YAG laser micro-chip,the Yb:YAG crystal frequency doubling laser performance was studied.The results showed that:in condition of the use of green light output mirror, the laser performance is better. Threshold power is 461mW, the output power and actual output power is 72.27mW,101.18 mW, respectively. Light-light conversion efficiency is up to 6.57%, slope efficiency is equal to 7.02%.(7). The laser ceramic powders were synthesized by using sol-gel and carbonate altogether precipitation methods, and reaction mechanism and influencing factors were discussed. The structure, morphology and spectral properties were studied by several measurements, such as TG-DTA, XRD, IR, TEM, spectral analysis and so on.(8). The Yb:YAG ceramic material of high quality was prepared through the technics of calcining, forming and sintering to precursor. The structures of prepared samples were analyzed through a series of measurements, and the microstructure of information was obtained. Moreover, the factors to affecting transparent ceramic and laser properties have been analyzed and studied deeply.