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Updated: Jul 9, 2026
12:18
Microwave Photonics Systems Based on Whispering-gallery-mode Resonators
Published on: August 5, 2013
Microtorus: a high-finesse microcavity with whispering-gallery modes
Optics Letters
|November 28, 2007
Summary
Researchers developed a novel oblate spheroidal microcavity. This dielectric microcavity offers a large free spectral range and high quality factor, beneficial for optical applications.
Area of Science:
- Photonics and optical engineering
- Materials science
Background:
- Whispering-gallery mode (WGM) microcavities are crucial for various optical applications.
- Traditional microspherical cavities exhibit a high Q factor but suffer from a high mode density and small free spectral range (FSR).
Purpose of the Study:
- To demonstrate a novel oblate spheroidal dielectric microcavity with enhanced optical properties.
- To investigate the potential of this microcavity for applications requiring a large FSR and high Q factor.
Main Methods:
- Fabrication of a 165-µm oblate spheroidal microcavity.
- Characterization of the microcavity's optical properties, including FSR, resonance bandwidth, and finesse at 1550 nm.
Main Results:
- Achieved a large free spectral range (FSR) of 383.7 GHz (3.06 nm).
- Obtained a resonance bandwidth of 23 MHz, corresponding to a high quality factor (Q) of approximately 10^7.
- Demonstrated a finesse (F) greater than or equal to 10^4.
- Significantly reduced the number of excited whispering-gallery modes by two orders of magnitude compared to microspheres.
Conclusions:
- The oblate spheroidal microcavity successfully combines a high Q factor with a vastly reduced mode density.
- The large FSR makes this novel microcavity highly desirable for spectral analysis, narrow-linewidth optical and radio frequency (RF) oscillators, and cavity quantum electrodynamics (QED).
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