Physical Sciences and Mathematics Commons^™

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 …