[14] X. F. Jiang, Y. F. Xiao, C. L. Zou, L. He, C. H. Dong, B. B. Li, Y. Li, F. W. Sun, L. Yang, Q. H. Gong. Highly unidirectional emission and ultralow-threshold lasing from on-chip ultrahigh-Q microcavities. Adv. Mater., 24, OP260-OP264(2012).
[40] R. G. Hunsperger. Theory of Optical Waveguides(2009).