Two-color pump-probe system broadly tunable over the visible and the near infrared with sub-30 fs temporal resolution

We describe an ultrafast spectroscopy system based on two synchronized noncollinear optical parametric amplifiers (NOPAs). Each NOPA can be independently configured to generate ultrabroadband sub-10 fs visible pulses, tunable 15 fs visible pulses (500-720 nm), tunable 15-30 fs near-infrared pulses (900-1500 nm), and 15-20 fs blue pulses (430-480 nm). This system enables to perform pump-probe experiments over nearly two octaves of spectrum with unprecedented temporal resolution. We present application examples highlighting the capability of this instrument to track excited-state dynamics occurring on the sub-100 fs time scale: electron transfer in polymer-fullerene blends, intersubband energy relaxation in carbon nanotubes, and internal conversion in carotenoids. (c) 2006 American Institute of Physics.