Title Approach to optical interference fringes reduction in diode laser absorption spectroscopy
Authors Linda Persson, Fredrik Andersson, Mats Andersson, Sune Svanberg
Full-text Available as PDF
Alternative Location http://dx.doi.org/10.1007/s..., Restricted Access
Publication Applied Physics B - Optics & Lasers
Year 2007
Volume 87
Issue 3
Pages 523 - 530
Document type Article
Status Published
Quality controlled Yes
Language eng
Publisher Springer Berlin / Heidelberg
Abstract English The advantage of a new scheme for balanced detection has been investigated to reduce the influence of optical interference fringes when performing diode laser gas absorption spectroscopy employing lock-in amplifiers and pigtailed lasers. The influence of the fringes has been reduced by comparing the lock-in 2 f signal due to the gas sample with that of a reference beam. The frequency regions outside the absorption feature have been used to obtain information on the interference fringe impact on the signal of interest. We have demonstrated an efficient way to reduce the influence of such fringes by employing this technique combined with non-linear signal processing methods. The different steps of the algorithm are presented. In the experimental arrangement presented, a reduction of the optical interference fringes by about 10 times is achieved, as demonstrated in measurements on molecular oxygen around 761 nm. The new technique is compared with an analog technique for balanced detection and certain advantages of the computer algorithm are pointed out. In particular, the emerging field of gas spectroscopy in scattering solid media strongly benefits from the technique presented.
ISBN/ISSN/Other ISSN: 0946-2171

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