Preparation And Properties Of Y₂O₃ Single Crystal And Photonic Crystals

Since the solid-state laser is small in size,easy to use and with the characteristic of high output power,it has been widely favored since its inception.Laser materials and resonators are key components that determine the performance of solid-state lasers.Nd:Y₂O₃ has a good overall performance,especially the thermal conductivity is about twice as the Nd:YAG single crystal,and can achieve higher laser efficiency,thus becoming the most likely to replace the Nd:YAG single crystal laser material.And yttrium oxide can be used as raw material to prepare photonic crystal structure for laser resonator,it can greatly improve the brightness and monochromaticity of laser.In this paper,the high-melting-point Nd:Y₂O₃ single crystal is fabricated by the improved flame melting method by controlling the heating rate and cutting speed,and the opal template of yttrium oxide photonic crystal is prepared by self-assembly method.Powder is prepared by ball milling method with(Y_0.991Nd_0.009)₂O₃ as raw materials,then prepared by solid phase synthesis,calcined at different temperature and kept for different time,the best comprehensive performance was obtained under the condition that the calcined temperature is 1550? and the holding time is 24h.The flowability of the powder is 30.02s/50g,the degree of compression is 13.29%,the uniformity is 1.9418,the crystallinity and the luminescent performance are excellent.ANSYS software was used to simulate the temperature field of crystal grown by flame melting method,and the influence of hydrogen flow rate,nozzle size and observation hole height on the temperature field was analyzed.The simulation results are used to guide the experiment to determine that under the condition that the nozzle size is 5mm,the observation hole located 110mm away from the nozzle,the hydrogen flow rate is 24L/min,oxygen flow rate is 9.5L/min,the crystal appears sharp polycrystalline nucleus,and gradually complete the formation of seed and shoulder diameter growth,then a crack-free crystal with a diameter of 4 mm and a length of about 20 mm can be obtained.The crystal grows in the direction of<111>,with a light blue color,a density of 5.0154 g/cm3 and a Vickers hardness of 1556.6Hv.Absorption peaks at 531 nm,588 nm,750 nm,808 nm,and 879 nm were observed,and the absorption peaks at 588 nm,750 nm,and 879 nm were most pronounced,which coincided with the position of the standard absorption peak of Nd.The absorption bands of these three bands are relatively wide and can match the LD emission wavelength better,which is favorable to the laser diode pump.It is found that microcracks,inclusions and dislocations are the main defects in the crystal defects.And it is important to improve the uniformity of the powders and the size of the nozzles in the preparation of large-size crystals.Spherical yttrium oxide precursors were synthesized by urea homogeneous precipitation method.The effect of reactant concentration on colloidal particle size and homogeneity was discussed.When the concentration of yttrium nitrate is 0.015mol/L,urea is 1mol/L and the volume of mixed solution is 500mL,the particle size distribution range is small and the standard deviation is 0.13461.The effect of dispersant and pH on the stability of yttrium oxide precursor suspension was analyzed.It was determined that ammonium citrate was used as the dispersant,and when its concentration was 0.5wt%,the stability of yttrium oxide precursor suspension was the best.The effects of preparation method,evaporation rate and suspension concentration on the arrangement of the photonic crystal were investigated.When the particle concentration is 0.5wt%,the periodic monolayer photonic crystal structure can be prepared by the vertical sedimentation method at the evaporation temperature of 50?,which laid the foundation for the preparation of the opal structure of the yttrium oxide photonic crystal.