Yb: LuPO _{Growth Process And Performance 4} Crystals

This paper mainly focuses on the growth, quality and performance characterization of Yb ions doped rare earth phosphate crystals Yb:LuPO4. Firstly, the crystal growth experiments with the flux method in the system of Pb2P2O7flux were carried out, and the factors that affecting the crystal growth were explored. Then the quality and performance of the grown crystal was tested; On the basis of the disadvantages concluded in the crystal growth experiment with Pb2P2O7flux system, the flux system and the chemical co-precipitation synthesis of nanomaterials such as LuPO4and YbPO4were explored. A new kind of flux system suitable for the flux of top-seed crystal growth method was found and the synthesized LuPO4and YbPO4nanomaterials were used in the crystal growth experiment. The main research work and the results are as follows:(1) The growth of Yb:LuPO4crystal:The flux of spontaneous nucleation crystal growth method was used to explore the growth of Yb:LuPO4crystal under Pb2P2O7flux system, which indicated that the sheet and rod Yb:LuPO4crystal can be grown out in the system of Pb2P2O7; The infrared spectrum of the crystal was measured by the Nicolet5700type Fourier transform infrared spectrometer, and the absorption peaks corresponding to the chemical bonds of the crystal were found without any impure peak, which indicated that the grown crystals were relatively pure crystal and the fluxing agent did not enter into the crystal; The insufficiencies of the flux were analyzed, and the factors such as selection of flux, temperature field, cooling rate that influencing crystal growth process were discussed..(2) The structure and defects of Yb:LuPO4crystal:The single crystal structure of the obtained crystal was analyzed by X-ray single crystal diffractometer, which indicated that Yb:LuPO4crystal belongs to tetragonal crystal system and its space group is I41/amd. The crystal cell parameters are a=6.7950(12) A, c=5.9588(10) A, Z=4and the crystal density is6.51647g/cm3; The rocking curve of (100) face was measured by X-ray double crystal diffractometer, and the theory FWHM of (100) face of the Yb:LuPO4crystal was calculated as9.6" at the first time. Then the cause of the widening FWHM was analyzed by comparing the theory value with the actual measured value; The morphology of plate and rod crystal was observed by optical microscope, and the crystal defects were observed by TEM. The cause of these two kinds of crystal form was analyzed according to the theory of PBC model.(3) Basic optical performance test of Yb:LuPO4crystal:The absorption spectra of5%doping concentration of Yb:LuPO4crystal was measured by the Cary500UV-VIS-NIR spectrophotometer, and the absorption peaks were found near975nm, consistent with the theory value of absorption peak of Yb ion; The absorption cross sections of the absorption peaks in π-polarization and σ-polarization were calculated respectively. Compared with Yb ion doped vanadate crystal compare salts, the absorption cross section and the line width of Yb:LuPO4crystal were relatively large. It shows that Yb:LuPO4crystal may have a more superior performance, and it is a kind of very potential laser materials.(4) Exploration of the new flux system:On the basis of the disadvantages of Pb2P2O7flux system in the process of crystal growth and the needs of large size crystal by using the top-seeded solution growth (TSSG) method, the new lead-free flux system (Li2CO3/Na2CO3-MoO3) was explored. Firstly, the synthesis methods of raw material (LuPO4and YbPO4) ingredients were explored for the crystal growth. The conditions of chemical co-precipitation method such as the reaction temperature, the pH of the solution, precipitant drop order were explored, and finally LuPO4and YbPO4nano powders were synthesized. The crystal growth experiment was carried out by the flux of spontaneous nucleation method and the conditions of crystal growth such as temperature field and cooling rate were explored. The crystals were grown out successfully, which indicated this flux system was feasible to grow Lanthanide phosphate crystal and could be used for the top-seeded solution growth method to obtain a large crystal.