Abstract

Whispering gallery mode (WGM) microresonators have been extensively studied since decades for their unique properties like large Q-factor, long photon lifetime storage and small optical volume. Those unique features allow to demonstrate linear, non-linear and quantum photonic devices based on WGM resonators [1]. Despite the huge interest for those compact microresonators, they have been mainly studied in the near infrared region. Since few years, the need of short wavelength compact coherent sources like single-frequency lasers and optical frequency combs, as tools for high precision spectroscopy [2], pushes the research community to investigate the potential of WGM resonators at short wavelengths. Mainly millidisk configurations have been investigated with record Q-factors estimated to be as high as 10⁹ at 370 nm [3]. However, microsphere resonator shape can be of interest in particular for QED experiment where high-Q factor should be associated with small cavity volume.

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