Open Access. Powered by Scholars. Published by Universities.®
Physical Sciences and Mathematics Commons™
Open Access. Powered by Scholars. Published by Universities.®
Articles 1 - 2 of 2
Full-Text Articles in Physical Sciences and Mathematics
Resolution Of Overlapping Spectra By Wavelength Modulation Spectroscopy, Audra Michiele Bullock
Resolution Of Overlapping Spectra By Wavelength Modulation Spectroscopy, Audra Michiele Bullock
Electrical & Computer Engineering Theses & Dissertations
Wavelength modulation absorption spectroscopy is a highly sensitive, non-intrusive technique for probing gaseous species, which employs the well-known principles of modulation spectroscopy in a novel way. With this technique, parameters such as velocity, density, and temperature can be measured with a high degree of precision. The research presented here shows that wavelength modulation is a convenient means of increasing the sensitivity of an absorption spectroscopy measurement because it allows for harmonic detection. The focus of the dissertation is resolution of overlapping spectra by harmonic detection and the advantages gained by performing detection at the higher harmonics, e.g., sixth and eighth. …
The Effects Of Fabry-Perot Fringing On The Sensitivity Of A Wavelength Modulation Experiment, Patrick C. Shea
The Effects Of Fabry-Perot Fringing On The Sensitivity Of A Wavelength Modulation Experiment, Patrick C. Shea
Electrical & Computer Engineering Theses & Dissertations
Parasitic Fabry-Perot etaloning plagues many experiments which use wavelength modulation spectroscopy. This fringing, which is an artifact that almost always appears in such experiments, arises from multiple reflections in the optical elements in the experimental apparatus. The etaloning plays a detrimental role and limits the ultimate sensitivity of wavelength modulation spectroscopy experiments. The research described in this thesis investigates this phenomenon. Experimental results are presented which show that when the Q-factor of the parasitic etalon is smaller that that of the absorption line being measured, significant improvement in the Signal to Fringe Noise Ratio can be obtained through the use …