Modeling whispering gallery modes in quantum dot embedded polystyrene microspheres

Whispering gallery modes (WGMs) have been demonstrated in polystyrene microspheres embedded with quantum dots (QDs) in the periphery to serve as local light sources for the remote excitation of low Q-factor microsphere sensors. These sensors were shown to display varied WGM spectra and refractometric sensitivity exceeding that predicted for a homogeneous microsphere. To explain these differences from the basic Mie scattering theory, the QDs have been modeled as a thin high index outer layer. This model has been shown to provide a good fit of the observed WGM spectra, with calculated values for the QD layer refractive index and penetration depth falling within our observed estimates. The possible enhancement in sensitivity for these microspheres has also been determined.

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