| Autor: |
P. Gill, M. Stevens, R. Benyon, C S Edwards, P Mackrodt, B Schirmer, G P Barwood |
| Rok vydání: |
2002 |
| Předmět: |
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| Zdroj: |
2000 Digest of the LEOS Summer Topical Meetings. Electronic-Enhanced Optics. Optical Sensing in Semiconductor Manufacturing. Electro-Optics in Space. Broadband Optical Networks (Cat. No.00TH8497). |
| DOI: |
10.1109/leosst.2000.869706 |
| Popis: |
There is an increasing demand for the measurement of trace humidity in air at levels down to a few parts in 10/sup 9/ (ppb/sub v/) at atmospheric pressure. This summary describes the development by a European collaboration of a diode laser absorption spectrometer capable of measuring trace humidity with an uncertainty of 5 ppb. The diode laser was a distributed feedback device, tuned to the 3,0,3/spl larr/2,0,2 rotation transition in the /spl nu//sub 1/+/spl nu//sub 3/ vibrational band of water vapour at 1393 nm. Two-tone frequency modulation spectroscopy (TTFMS) was chosen as it combines the advantages of being the most sensitive technique and is relatively straightforward to implement. After a number of refinements to the optical layout, TTFMS features were obtained with no observable background interference effects. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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