Dielectric perturbations: anomalous resonance frequency shifts in optical resonators

Small perturbations in the dielectric environment around a high quality whispering gallery mode resonator usually lead to a frequency shift of the resonator modes directly proportional to the polarizability of the perturbation. Here, we report experimental observations of strong frequency shifts tha...

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Bibliographic Details
Published inarXiv.org
Main Authors Azeem, Farhan, Trainor, Luke S, Devane, Patrick A, Norman, Daniel S, Rueda, Alfredo, Lambert, Nicholas J, Kumari, Madhuri, eman, Matthew R, Schwefel, Harald G L
Format Paper Journal Article
LanguageEnglish
Published Ithaca Cornell University Library, arXiv.org 23.12.2020
Subjects
Frequency shift
Lithium niobates
Optical resonators
Perturbation
Physics - Optics
Refractivity
Substrates
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Summary:Small perturbations in the dielectric environment around a high quality whispering gallery mode resonator usually lead to a frequency shift of the resonator modes directly proportional to the polarizability of the perturbation. Here, we report experimental observations of strong frequency shifts that can be opposite and even exceed the contribution of the perturbations' polarizability. The mode frequencies of a lithium niobate whispering gallery mode resonator are shifted using substrates of refractive indices ranging from 1.50 to 4.22. Both blue- and red-shifts are observed, as well as an increase in mode linewidth, when substrates are moved into the evanescent field of the whispering gallery mode. We compare the experimental results to a theoretical model by Foreman et al. and provide an additional intuitive explanation based on the Goos-H\"anchen shift for the optical domain.
ISSN:2331-8422
DOI:10.48550/arxiv.2012.12446