High-information time-resolved Fourier transform spectroscopy at work

The first instrumental setup, to our knowledge, that is capable of recording in a few hours the time-resolved Fourier transform (TRFT) interferograms of gas-phase spectra that cover several thousands of inverse centimeters with spectral- and time-resolution limits that are equal, at best, to 2.5 x 10(-3) cm(-1) and 2 ns, respectively, is reported. It was developed on the stepping-mode Connes-type interferometer of the Laboratoire de Photophysique Moleculaire Universite de Paris Sud. Also, for the first time, to our knowledge, these high-resolution TRFT spectra, illustrated with the Doppler-limited emission spectra of the N-2 transitions (B-A) and (B'-B) between 5500 and 11 000 cm(-1) and of the atomic Ar Lines between 1800 and 4000 cm(-1), are recorded in the infrared spectral range. To obtain identical results that have the same signal-to-noise ratio, we should have increased the recording time of our unique previous high-information TRFT spectra by approximately 50,000. In other words, one hour is now long enough to obtain what would previously have required six years to record. (C) 2000 Optical Society of America OCIS codes: 300.6500, 300.6300, 120.3180.