Sensitive multiplex spectroscopy in the molecular fingerprint 2.4 mum region with a Cr(2+):ZnSe femtosecond laser.
An ultrashort-pulse Cr(2+):ZnSe laser is a novel broadband source for sensitive high resolution molecular spectroscopy. A 130-fs pulse allows covering of up to 380 cm(-1) spectral domain around 2.4 mum which is analyzed simultaneously with a 0.12 cm(-1) (3.6 GHz) resolution by a Fouriertransform spectrometer. Recorded in 13 s, from 70-cm length absorption around 4150 cm(-1), acetylene and ammonia spectra exhibit a 3800 signal-tonoise ratio and a 2.4.10(-7) cm(-1).Hz(-1/2) noise equivalent absorption coefficient at one second averaging per spectral element, suggesting a 0.2 ppbv detection level for HF molecule. With the widely practiced classical tungsten lamp source instead of the laser, identical spectra would have taken more than one hour.
Sorokin
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E
Sorokina
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IT
Mandon
J
J
Guelachvili
G
G
Picque
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N