【摘要】 用坩埚下降法技术,选用同成分化学计量的铌酸锂为初始原料,在合适的生长速度(1~4mm/h)与温度梯度(20~30℃/cm)下成功地生长出了无宏观缺陷、掺杂不同Cr3+离子浓度的铌酸锂单晶。测定了晶体的吸收光谱。Cr3+ 离子在晶体中以三价态存在,沿着生长方向晶体中 Cr3+ 离子的含量逐步减少。用顺磁共振谱(EPR)研究了晶体中 Cr3+离子的格位情况,结果表明Cr3+离子取代 Li 与 Nb 两种格位。测定了晶体的发射光谱并研究了发射强度随吸收强度的变化关系。更多还原

【Abstract】 The LiNbO₃ crystals doped with Cr³⁺ ion （Cr∶LN） in various concentration without macro-defects were grown by Bridgman method under proper conditions in congruent composition （Li/Nb=48.6/51.4 in molar ratio）, growth rate of 1～3mm/h, and a temperature gradient around 20～30℃/cm for solid-liquid interface. The absorption spectra of the obtained crystals were measured. The Cr ions exist in state of +3. The concentration of Cr³⁺ ion in crystal increased from lower to upper portion. Electron paramagnetic resonance had been used to investigate the sites occupied by the Cr³⁺ ions. Two Cr³⁺ ion centers located at Li⁺ and Nb⁵⁺ sites were observed. The fluorescence spectra were recorded and the relation between intensity of fluorescence and their absorption coefficient was investigated.更多还原