We fabricate slightly deformed fused-silica microspheres in which whispering gallery modes possess remarkably directional escape emission from the microsphere boundary. With efficient free-space excitation and collection, the lateral spatial distribution of whispering gallery modes with different azimuthal mode numbers, m, is directly observed through modal coupling and directional emission. Excellent agreement with theory is obtained.
© 2008 Chinese Optics Letters
Chunhua Dong, Yunfeng Xiao, Yong Yang, Zhengfu Han, Guangcan Guo, and Lan Yang, "Directly mapping whispering gallery modes in a microsphere through modal coupling and directional emission," Chin. Opt. Lett. 6, 300-302 (2008)