Thermostable refractive index sensors based on whispering gallery modes in a microsphere coated with poly(methyl methacrylate)

Nai Lin, Lan Jiang, Sumei Wang, Hai Xiao, Yongfeng Lu, Hailung Tsai

Research output: Contribution to journalArticle

21 Scopus citations


This study proposes a thermostable refractive index (RI) sensor consisting of a silica microsphere coated with a poly(methyl methacrylate) (PMMA) layer. The first-order and second-order whispering gallery modes (WGMs) of both TE and TM polarizations are considered theoretically. The layer thickness is carefully optimized to eliminate the thermal drift and enhance the RI sensitivity and detection limit. In various WGMs, at the thermostable thickness of the PMMA layer, the first-order TM mode corresponds to the highest sensitivity and the smallest detection limit. The theoretical predictions provide guidelines for the design and fabrication of thermostable RI sensors.

Original languageEnglish (US)
Pages (from-to)992-998
Number of pages7
JournalApplied optics
Issue number7
Publication statusPublished - Mar 1 2011


ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics
  • Engineering (miscellaneous)
  • Electrical and Electronic Engineering

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