Abstract
Over the past few years, high sensitivity spectroscopic techniques have gained in efficiency and several experimental schemes now enable to reach ppb detection levels. One of the prevailing quests presently aims at combining these sensitivities with rapid diagnostic and/or multi-species gas analysis. This induces new approaches able to couple broadband coherent sources to multiplex or multichannel spectrometers. Nowadays at high spectral resolution, simultaneous spectral coverage is still often restricted to a few nanometers due to multichannel grating spectrometer limitation and/or to narrow spectral range optical source capabilities. With the breakthrough of mode-locked femtosecond (fs) lasers and frequency combs, extremely broad "steady state" high quality coherent sources have become available. This prompted the need for related spectral approaches able to deliver at once high resolution, high accuracy, broad spectral coverage and rapid acquisition. Purposely, a broadband frequency comb was coherently coupled [1] to a high finesse cavity across 100 nm, with an equivalent absorption path equal to 1.13 km. Nevertheless, due to lack of appropriate spectroscopic method, this recent impressive experiment provided simultaneous spectral results limited to 15 nm, 25 GHz resolution with signal to noise ratio (SNR) of the order of 15. Finally with the same purpose, a broadband cw Cr2+:ZnSe laser used for intracavity absorption spectroscopy was coupled [2] to a high resolution time-resolved Fourier transform interferometer. A simultaneous coverage of 125 nm was obtained with 330 MHz resolution, 2.5 km equivalent absorption path length and SNR equal to 100.
© 2007 IEEE
PDF ArticleMore Like This
Ming Yan, Pei-Ling Luo, Kana Iwakuni, Guy Millot, Theodor W. Hänsch, and Nathalie Picqué
LT1G.3 Laser Applications to Chemical, Security and Environmental Analysis (LACSEA) 2016
Ming Yan, Pei-Ling Luo, Kana Iwakuni, Guy Millot, Theodor W. Hänsch, and Nathalie Picqué
SW4H.4 CLEO: Science and Innovations (CLEO:S&I) 2016
Julien Mandon, Guy Guelachvili, and Nathalie Picqué
ID3_2 International Quantum Electronics Conference (IQEC) 2007