【摘要】 采用液相共沉淀方法,制备了纳米材料Yb:LuScO3。X射线衍射分析结果表明,它的晶格参数为a=1.0126nm,粒度为50nm。在937nm光激发下,发射谱带很宽,发射峰分别位于976,1037,1085nm。通过漫反射吸收光谱,确定零吸收线在976nm处,能级分裂达1029cm-1,表明它的晶场分裂比较大。更多还原

【Abstract】 Yb3+ is a good active ion.It has the simplest level structure,consisting of only two multiplets 2F7/2 and 2F5/2,which results in several advantages,such as no excited state absorption,no more up-conversion,and low quantum defect able to reduce the thermal loading.In addition,the longer fluorescence lifetime(about 1 ms) is propitious to store energy and the broad emission band allows the generation of high power laser pulse.But Yb3+ can only operate in a quasi-three level scheme.The terminal state of laser emission is very close to ground state,which results in high thermal population of the laser terminal state and strong re-absorption at the emission wavelengths,and high laser pumping threshold.In order to limit thermal population of the terminal level,a relatively strong crystal field increasing the Stark-splitting of the Yb3+ ground manifold as large as possible is expected.In our experiment,we discover that Yb3+ has bigger stronger Stark-splitting in the crystalline field of LuScO3.We take ammonia as precipitator,Yb2O3,Sc2O3 and Lu2O3 as starting mate-rials to prepare Yb∶LuScO3 precursor by co-precipitation method.We obtained Yb∶LuScO3 nano-polycrystalline powders by sintering the precursor at 1 500 ℃.X-ray powder diffraction indicated that the polycrystalline Yb∶LuScO3 belongs to the cubic phase,space group Ia3.Its lattice parameter a is 1.012 6 nm,calculated by the least square method,and its size is about 50 nm.When excited at 937 nm,the strongest emission peaks of Yb∶LuScO3 are at 976 nm and 1 037 nm,the weaker peak at 1 085 nm.According to its emission and absorption spectra,the energy structure of Yb3+ is determined.The overall splitting value of 2F7/2 is 1 029 cm-1,which is larger than 785 cm-1 of Yb∶YAG.By comparison to emission spectrum with Yb∶YAG,the emission peaks move to longer wavelength and the emission spectrum band is very wide,which advantages to decrease laser threshold and improves laser efficiency.In addition,the broader emission band of Yb∶LuScO3 is propitious to ultra-short pulses output.更多还原