Deflecting light into resonant cavities for spectroscopy

Patent · Wed Dec 31 23:00:00 EST 1997

OSTI ID:871873

Zare, Richard N ^[1]; Martin, Juergen ^[2]; Paldus, Barbara A ^[1]

---

1. Stanford, CA
2. Harxheim, DE

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.

• Research Organization: Stanford University
• DOE Contract Number: FG03-92ER14304
• Assignee: Board of Trustees of Leland Stanford Junior Univesity (Stanford, CA)
• Patent Number(s): US 5815277
• OSTI ID: 871873
• Country of Publication: United States
• Language: English

Related Subjects

/356/
40
acousto-optic
acousto-optic modulator
allow
allows
aom
available
cavities
cavity
cavity mirror
conventional
coupled
crds
deflecting
deflection
detectors
devices
efficiencies
electro-optic
electro-optic modulator
elements
excess
far-infrared
fast-responding
in-coupling
input
insensitive
intensities
lead
light
light intensities
magnitude
method
mid-infrared
mirror
mirrors
moderately
modulator
modulators
noise
particularly
particularly useful
photovoltaic
q-switching
ranges
reduction
reflecting
relatively
relatively insensitive
resonant
resonant cavities
resonant cavity
roundtrip
shorter
shot
shutoff
spectroscopy
systems
time
trip time
ultraviolet
ultraviolet wavelength
useful
wavelength
wavelength range
wavelength ranges
widely