Sensitive absorption measurements in the near-infrared region using off-axis integrated-cavity-output spectroscopy
| Autor: | Joshua B. Paul, Douglas S. Baer, Manish Gupta, Anthony O'Keefe |
|---|---|
| Rok vydání: | 2002 |
| Předmět: |
Materials science
Physics and Astronomy (miscellaneous) Absorption spectroscopy business.industry Near-infrared spectroscopy Far-infrared laser General Engineering General Physics and Astronomy Laser Semiconductor laser theory law.invention Optics Optical path law Optical cavity business Optical path length |
| Zdroj: | Applied Physics B: Lasers and Optics. 75:261-265 |
| ISSN: | 1432-0649 0946-2171 |
| DOI: | 10.1007/s00340-002-0971-z |
| Popis: | A novel instrument that employs a high-finesse optical cavity as an absorption cell has been developed for sensitive measurements of gas mixing ratios using near-infrared diode lasers and absorption-spectroscopy techniques. The instrument employs an off-axis trajectory of the laser beam through the cell to yield an effective optical path length of several kilometers without significant unwanted effects due to cavity resonances. As a result, a minimum detectable absorption of approximately 1.4×10-5 over an effective optical path of 4.2 km was obtained in a 1.1-Hz detection bandwidth to yield a detection sensitivity of approximately 3.1×10-11 cm-1 Hz-1/2. The instrument has been used for sensitive measurements of CO, CH4, C2H2 and NH3. |
| Databáze: | OpenAIRE |
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