Deflecting light into resonant cavities for spectroscopy
Light is coupled into a cavity ring down spectroscopy (CRDS) resonant cavity using an acousto-optic modulator. The AOM allows in-coupling efficiencies in excess of 40%, which is two to three orders of magnitude higher than in conventional systems using a cavity mirror for in-coupling. The AOM shutoff time is shorter than the roundtrip time of the cavity. The higher light intensities lead to a reduction in shot noise, and allow the use of relatively insensitive but fast-responding detectors such as photovoltaic detectors. Other deflection devices such as electro-optic modulators or elements used in conventional Q-switching may be used instead of the AOM. The method is particularly useful in the mid-infrared, far-infrared, and ultraviolet wavelength ranges, for which moderately reflecting input mirrors are not widely available. 5 figs.
- Research Organization:
- Stanford Univ., CA (United States)
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- FG03-92ER14304
- Assignee:
- Leland Stanford Junior Univ., Stanford, CA (United States)
- Patent Number(s):
- US 5,815,277/A/
- Application Number:
- PAN: 8-949,242
- OSTI ID:
- 672693
- Resource Relation:
- Other Information: PBD: 29 Sep 1998
- Country of Publication:
- United States
- Language:
- English
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Ring resonant cavities for spectroscopy
Ring resonant cavities for spectroscopy