“…Due to high Q and minimal mode volume, as well as simple construction techniques and easy integration, Whispering Gallery Mode Resonators (WGMRs) [1] have been attracted for many applications, including optic gyroscopes [2], tunable add-drop filters [3], all-optical switch [4], ultra-low threshold lasers [5][6][7], labelfree detection [8][9][10], pressure measurement [11], thermal sensing [12], etc. A variety of rotationally symmetric WGMR with high Qvalue have been fabricated, including microsphere [13], microdisk [14], microtoroid [15], and microtubular [16].…”