caa a22 4500 445372125 CHVBK 20180317142950.0 cr unu---uuuuu 170323e20110301xx s 000 0 eng 10.1007/s00340-010-4248-7 doi (NATIONALLICENCE)springer-10.1007/s00340-010-4248-7 Characterization of lineshape structure by wavelength modulation spectroscopy [Elektronische Daten] [K. Mohan, M. Khan, A. Dharamsi] Wavelength Modulation Spectroscopy (WMS) is performed in the oxygen A-band at different harmonics for different modulation indices and optical pathlengths. The experimental data is compared to two models with different absorption profiles: one assuming a Lorentzian lineshape function and the other with a Voigt lineshape function. We show that the larger amount of structure in higher harmonic signals provides greater sensitivity to the type of lineshape profile utilized for modeling. A useful new feature explored in this work is optical path length saturation in WMS that was described for the first time in a recent paper from our group. We discuss the role of such saturation and how it can be utilized as a diagnostic to probe lineshape. We also address the effect of the ever present modulation broadening. Results of experiments in which sets of nine scans (direct absorption, 1f, 2f, ,8f; i.e., detection harmonic N=0,1,2,3, ,8) were made simultaneously are described and discussed. Finally, the role that increased structure plays—as a result of increasing order of detection, N, as well as from the modification of the signal profile with increasing optical thickness—is outlined from the perspective of classical information theory. Springer-Verlag, 2010 Mohan K. Department of Electrical and Computer Engineering, Old Dominion University, 23529, Norfolk, VA, USA aut Khan M. Department of Electrical and Computer Engineering, Old Dominion University, 23529, Norfolk, VA, USA aut Dharamsi A. Department of Electrical and Computer Engineering, Old Dominion University, 23529, Norfolk, VA, USA aut Applied Physics B Springer-Verlag 102/3(2011-03-01), 569-578 0946-2171 102:3<569 2011 102 340 https://doi.org/10.1007/s00340-010-4248-7 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s00340-010-4248-7 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Mohan K. Department of Electrical and Computer Engineering, Old Dominion University, 23529, Norfolk, VA, USA aut NATIONALLICENCE 700 1- Khan M. Department of Electrical and Computer Engineering, Old Dominion University, 23529, Norfolk, VA, USA aut NATIONALLICENCE 700 1- Dharamsi A. Department of Electrical and Computer Engineering, Old Dominion University, 23529, Norfolk, VA, USA aut NATIONALLICENCE 773 0- Applied Physics B Springer-Verlag 102/3(2011-03-01), 569-578 0946-2171 102:3<569 2011 102 340 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer