Optical heterodyne detection for cavity ring-down spectroscopy
US6094267A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 21, 1999 |
| Grant date | Jul 25, 2000 |
| Priority date | — |
| Expiry date | Apr 21, 2019 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N2021/391
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A cavity ring-down system for performing cavity ring-down spectroscopy (CRDS) using optical heterodyne detection of a ring-down wave E.sub.RD during a ring-down phase or a ring-up wave E.sub.RU during a ring up phase. The system sends a local oscillator wave E.sub.LO and a signal wave E.sub.SIGNAL to the cavity, preferably a ring resonator, and derives an interference signal from the combined local oscillator wave E.sub.LO and the ring-down wave E.sub.RD (or ring-up wave E.sub.RU). The local oscillator wave E.sub.LO has a first polarization and the ring-down wave E.sub.RD has a second polarization different from the first polarization. The system has a combining arrangement for combining or overlapping local oscillator wave E.sub.LO and the ring-down wave E.sub.RD at a photodetector, which receives the interference signal and generates a heterodyne current I.sub.H therefrom. Frequency and phase differences between the waves are adjustable.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.