We demonstrate a 165-mu;m oblate spheroidal microcavity with a free spectral range of 383.7 GHz (3.06 nm), a resonance bandwidth of 23 MHz (quality factor Q≈10<sup>7</sup>) at 1550 nm, and finesse F≥10<sup>4</sup> . The highly oblate spheroidal dielectric microcavity combines a very high Q factor, typical of microspheres, with a vastly reduced number of excited whispering-gallery modes (by 2 orders of magnitude). The very large free spectral range in this novel microcavity–a few hundred gigahertz instead of a few gigahertz as in typical microspheres—is desirable for applications in spectral analysis, narrow-linewidth optical and rf oscillators, and cavity QED.
© 2001 Optical Society of America
(060.2340) Fiber optics and optical communications : Fiber optics components
(120.2440) Instrumentation, measurement, and metrology : Filters
(140.4780) Lasers and laser optics : Optical resonators
(230.3990) Optical devices : Micro-optical devices
Vladimir S. Ilchenko, Michael L. Gorodetsky, X. Steve Yao, and Lute Maleki, "Microtorus: a high-finesse microcavity with whispering-gallery modes," Opt. Lett. 26, 256-258 (2001)