  Supercontinua generated in highly non-linear fibers by ultrashort-pulse
lasers can be used for high resolution Fourier transform absorption
spectroscopy. The practical advantages of these bright ultrabroadband light
sources for spectroscopy are reported in the near-infrared region. A Cr^4+:YAG
femtosecond laser broadened by an extruded soft-glass photonic crystal fiber,
emitting from 1200 to 2200 nm and from 675 to 950 nm, provides a spectral
radiance being 1x10^5 times higher than that of a 3000 K blackbody and 10^2
times higher than that of a synchrotron radiation. The C_2H_2 and NH_3 overtone
spectra are recorded using this source within a few seconds.
