A picosecond time-resolved vibrational circular dichroism spectrometer

We present an experimental setup to detect transient vibrational circular dichroism signals. A femtosecond laser system is synchronized to a photoelastic modulator to produce alternating left- and right-handed circularly polarized mid-IR pulses at 1 kHz repetition rate. Transient changes in the circular dichroism of the CH-stretch vibrations of a cobalt-sparteine complex were probed in a proof-of-principle experiment and are clearly distinct from conventional transient absorption changes. (C) 2008 Optical Society of America