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

Abstract

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-10fs visible pulses, tunable 15fs visible pulses (500–720nm), tunable 15–30fs near-infrared pulses (900–1500nm), and 15–20fs blue pulses (430–480nm). 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-100fs time scale: electron transfer in polymer-fullerene blends, intersubband energy relaxation in carbon nanotubes, and internal conversion in carotenoids.