Frequency-domain "single-shot" (FDSS) transient absorption spectroscopy using a variable-length grating pair compressor

Single-shot ultrafast spectroscopy based on the frequency encoding of transient absorbance kinetics (FDSS) is demonstrated. These kinetics are sampled spectrally using linearly chirped pulses derived from a Ti:sapphire laser. A variable length grating pair compressor is used to provide group velocity dispersion out to -1.6 ps^2 and achieve the sampling of 512 channels per a 2-to-160 ps window with sensitivity > 5e-4. The possibilities of FDSS are illustrated with studies of three photon ionization of liquid water and one-photon excitation of a thin-film