TY - JOUR

T1 - Resonance shifts of counterpropagating whispering-gallery modes

T2 - Degenerate perturbation theory and application to resonator sensors with axial symmetry

AU - Teraoka, Iwao

AU - Arnold, Stephen

PY - 2009/7/1

Y1 - 2009/7/1

N2 - A theory is presented that considers the resonance shift of degenerate whispering-gallery modes (WGMs) in sensor applications. The theory is then applied to a pair of counterpropagating waves in a spheroidal resonator. Adsorption of a particle lifts the twofold degeneracy, resulting in a pair of standing waves with a symmetric field around the particle, a standing symmetric wave (SSW) and an antisymmetric wave (ASW). The shift for a SSW is twice as large as the one for a nondegenerate WGM when the particle radius is sufficiently smaller than the wavelength, whereas the shift for an ASW is nearly zero. The ratio of the split to the mean shift gives an estimate of the particle size, whereas the mean shift is sensitive to its polarizability. With an increasing particle radius, the ratio of the split to the mean shift decreases. There is a particle radius that maximizes the split.

AB - A theory is presented that considers the resonance shift of degenerate whispering-gallery modes (WGMs) in sensor applications. The theory is then applied to a pair of counterpropagating waves in a spheroidal resonator. Adsorption of a particle lifts the twofold degeneracy, resulting in a pair of standing waves with a symmetric field around the particle, a standing symmetric wave (SSW) and an antisymmetric wave (ASW). The shift for a SSW is twice as large as the one for a nondegenerate WGM when the particle radius is sufficiently smaller than the wavelength, whereas the shift for an ASW is nearly zero. The ratio of the split to the mean shift gives an estimate of the particle size, whereas the mean shift is sensitive to its polarizability. With an increasing particle radius, the ratio of the split to the mean shift decreases. There is a particle radius that maximizes the split.

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U2 - 10.1364/JOSAB.26.001321

DO - 10.1364/JOSAB.26.001321

M3 - Article

AN - SCOPUS:67849103848

VL - 26

SP - 1321

EP - 1329

JO - Journal of the Optical Society of America B: Optical Physics

JF - Journal of the Optical Society of America B: Optical Physics

SN - 0740-3224

IS - 7

ER -