Fine-tuning of whispering gallery modes in on-chip silica microdisk resonators within a full spectral range

R. Henze1, C. Pyrlik2, A. Thies2, J.M. Ward1,3, A. Wicht2, and O. Benson1

Published in:

Appl. Phys. Lett., vol. 102, no. 041104 (2013).

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We investigate an efficient method for fine-tuning whispering gallery mode resonances in disk-type silica microresonators to reach an arbitrary frequency within the free spectral range of the system. This method is based on a post-production hydrofluoric acid etching process to precisely resize the radius of such microresonators. We show the effectiveness of this approach by tuning their resonance frequency within 10 GHz of specific hydrogen cyanide reference lines (P16, P18). This technique allows for simple and exact matching of narrow-linewidth lasers or spectroscopic lines with the high-Q resonances of on-chip silica microresonators.

1 Department of Physics, Humboldt-Universität zu Berlin, Newtonstraße 15, 12489 Berlin, Germany
2 Ferdinand-Braun-Institut, Leibniz-Institut für Höchstfrequenztechnik, Gustav-Kirchhoff-Straße 4, D-12489 Berlin, Germany
3 Physics Department, University College Cork, Cork, Ireland