Dresden 2011 – wissenschaftliches Programm

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UP: Fachverband Umweltphysik

UP 8: Measurement Techniques

UP 8.3: Vortrag

Donnerstag, 17. März 2011, 14:45–15:00, HSZ 204

Probing of Air Components by Means of PCF-generated Supercontinuum and CRD-Spectrography — Kamil Stelmaszczyk¹, Walter Nakaema^1,2, •Zuo-Qiang Hao¹, Philipp Rohwetter¹, and Ludger Wöste¹ — ¹Institute of Experimental Physics, Free University of Berlin, Arnimallee 14, 14195 Berlin, Germany — ²Center for Lasers and Applications, Instituto de Pesquisas Energéticas e Nucleares, Av. Prof. Lineu Prestes 224, CEP: 05508-000, Sao Paulo-SP, Brazil

We explored the possibility of using the PCF generated supercontinuum light in broadband CRDS investigations of air constituents basing on the CRD-Spectrography scheme. The measurement setup comprised a single cavity, constituted by two spherical mirrors coated with highly reflective coatings (600-740 nm) and a single detection unit consisting of a Czerny-Turner spectrograph fitted with a full frame intensified CCD camera that were common for all wavelengths. In this way the final sensitivity of about 4.7x10-9 cm-1 was obtained. It was more than sufficient to detect weak overtone absorption (polyads 4v and 4v+delta) of molecular water and spin forbidden b-X transition of oxygen molecules directly in ambient air opening perspective for broadband atmospheric investigations of other environment relevant gases. The supercontinuum CRD-Spectrography provides a less complex alternative to Frequency Comb CRDS, which as compared to supercontinuum CEAS is not biased by the calibration issues related to poorly known reflectance of cavity mirrors.