Trace analysis of water pollutants by photothermal phase shift spectroscopy with an integrated optical microinterferometer

Werner N. Faubel; Bernd S. Seidel; Hans-Joachim Ache

doi:10.1117/12.221745

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29 September 1995 Trace analysis of water pollutants by photothermal phase shift spectroscopy with an integrated optical microinterferometer

Werner N. Faubel, Bernd S. Seidel, Hans-Joachim Ache

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Proceedings Volume 2508, Chemical, Biochemical, and Environmental Fiber Sensors VII; (1995) https://doi.org/10.1117/12.221745
Event: European Symposium on Optics for Environmental and Public Safety, 1995, Munich, Germany

Abstract

Photothermal phase shift spectroscopy measures the changes of the refractive index, induced by a modulated continous wave argon ion laser excitation light beam, by a double microinterferometer, consisting of an integrated optic silica chip of the sizes of 7.5 by 7.5 mm. As probe laser, a laser diode is used, which is integrated at the chip. The flow thorugh cell, containing the analyte, is mounted in one of the two arms of the Michelson interferometer between the microchip and the reflecting mirror. The great potential of this photothermal microinterferometer as a routine method for process control or environmental surveillance lies in the miniaturization of the system for the following reasons: no adjustment is needed because only fixed components are used. The quality of the light beam is significantly improved by shortening the light paths and very small sample cell volumes in the range of nl or (mu) l are needed. This has at least two distinct advantages. On the one hand, a small, compact analytical apparatus allows direct real time measurements and on site measurements. On the other hand, it is possible to built up a robust and reliable device, in one cast and without any movable part, unaffected by external influences.

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Werner N. Faubel, Bernd S. Seidel, and Hans-Joachim Ache "Trace analysis of water pollutants by photothermal phase shift spectroscopy with an integrated optical microinterferometer", Proc. SPIE 2508, Chemical, Biochemical, and Environmental Fiber Sensors VII, (29 September 1995); https://doi.org/10.1117/12.221745

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