石英毛细管中回音壁模式激光的波长漂移特性

Wavelength shift propriety of whispering gallery mode lasing in a quartz capillary

摘要: 利用石英毛细管截面构成的圆形微腔,从实验和理论2个方面研究了回音壁模式激光辐射随增益包层溶液的折射率以及染料浓度的变化特性.实验结果表明,随包层溶液折射率的增加,回音壁模式的激光辐射向短波方向漂移;随包层溶液中染料浓度的增加,回音壁模式的激光辐射向长波方向漂移.包层溶液折射率的增加导致微腔品质因数降低,而染料浓度的增加致使激光增益范围向长波方向扩展.基于如上分析,结合微腔理论和染料激光的四能级模型,成功地解释了实验结果.

Abstract: Quartz capillary was immersed into a mixed solution of ethanol and ethylene glycol doped by rhodamine 6G dye molecules and different dye concentration of ethylene glycol doped by rhodamine 6G solution, respectively. Pumped by evanescent-waves along the fiber axis, the lasing wavelength of Whispering Gallery Mode (WGM) has been found to blue shift with the increase of refractive index of dye solution and red shift with the increase of dye concentration. The experimental observations are well explained by the four-energy level model of dye lasing from a WGM fibre laser.