Abstract
We present the observation of critical coupling in a high- fused-silica microsphere whispering-gallery mode resonator coupled to a fiber taper. Extremely efficient and controlled power transfer to high- resonators has been demonstrated. Off-resonance scattering loss was measured to be less than . On-resonance extinction in transmitted optical power through the fiber coupler was measured as high as 26 dB at the critical coupling point. This result opens up a range of new applications in fields as diverse as near-field sensing and quantum optics.
- Received 17 December 1999
DOI:https://doi.org/10.1103/PhysRevLett.85.74
©2000 American Physical Society