Broadband ultrafast spectroscopy using a photonic crystal fiber:: application to the photophysics of malachite green

Femtosecond single-pulsed supercontinua (SC) are produced in a short sub-cm piece of photonic crystal fiber. The SC span from 450 nm to more than 1.1 mu m with 1-nJ energy injection. UV light down to 340 nm is observed with increased injection power. Using such a single-pulsed SC we implemented a compact transient absorption spectrometer with broadband detection and 150-fs FWHM time resolution to monitor the ultrafast dynamics of the electronic states of malachite green in ethanol excited to the S-2 state. The full spectral evolution is observed from 450 nm to 1050 nm, with high sensitivity and a signal-to-noise ratio as high as 1000. (c) 2007 Optical Society of America.