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Photothermal detection of trace optical absorption in water by use of visible light-emitting diodes
- Source :
- Applied Optics. Nov 1, 1998, Vol. 37 Issue 31, p7320, 7 p.
- Publication Year :
- 1998
-
Abstract
- Visible-light-emitting diodes of three different colors have been used to detect an absorbing compound (potassium permanganate) in trace quantities in aqueous solution. Photothermal absorption in a closed cell caused deflection of a water meniscus held at a small pinhole. The displacement was monitored with optical-fiber interferometry. The technique was limited by LED emission intensities and environmental acoustic noise, giving minimum detectable absorption coefficients of 2 x [10.sup.-4] [cm.sup.-1] at 478 and 658 nm and 3 x [10.sup.-4] [cm.sup.-1] at 524 nm. The magnitude and form of meniscus deflection signals were shown to be in good agreement with theory.
Details
- ISSN :
- 1559128X
- Volume :
- 37
- Issue :
- 31
- Database :
- Gale General OneFile
- Journal :
- Applied Optics
- Publication Type :
- Academic Journal
- Accession number :
- edsgcl.55509730