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Microwave Photonics Systems Based on Whispering-gallery-mode Resonators
Published on: August 5, 2013
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Efficient free-space read-out of WGM lasers using circular micromirrors
Optics Express
|April 4, 2015
Summary
We developed a micromirror technique to efficiently collect light from whispering-gallery mode (WGM) resonators. This method significantly enhances signal detection for WGM laser applications.
Area of Science:
- Optics
- Photonics
- Nanotechnology
Background:
- Whispering-gallery mode (WGM) resonators exhibit omnidirectional lasing in the azimuthal plane.
- Off-chip spectral analysis of WGM lasers is challenging due to in-plane emission and beam divergence, hindering efficient detection.
Purpose of the Study:
- To demonstrate a method for redirecting WGM laser emission from all azimuthal angles.
- To improve the efficiency and signal-to-noise ratio of WGM laser detection.
Main Methods:
- A circular micromirror was placed around the WGM cavity to redirect emission.
- Free-space optics were used to collect reflections from the micromirror.
- Vertical spontaneous emission was blocked to isolate WGM laser signals.
Main Results:
- Read-out intensity of WGM laser emission improved by one order of magnitude.
- Signal-to-noise ratio improved from 4.6 dB to 15 dB by blocking spontaneous emission and collecting micromirror reflections.
- The read-out concept is applicable to various WGM cavity geometries.
Conclusions:
- Redirecting WGM laser emission with a micromirror enhances detection efficiency.
- This technique significantly improves signal-to-noise ratio for WGM laser analysis.
- The method is versatile and does not compromise the resonator's quality factor.
