Ultrafast Microscope

The development of future materials and devices for applications such as light energy harvesting will ultimately depend on the understanding of photochemical and photophysical processes and their dynamics in the condensed phase. The investigation of nano- and micro-structured materials or quantum materials requires spatial as well as temporal. We therefore apply femtosecond pump-probe transient absorption spectroscopy through a optical microscope (Fig. 1) and achieve 50-100 fs temporal and 1-2 µm spatial resolution. A high repetition rate laser (40 kHz) allows for fast data acquisition and two NOPAs provide high flexibility for wavelength tuning of pump and probe pulses (500-950 nm, with additional SHG: 250-470 nm).

_{Fig. 1: The ultrafast microscope combines pump-probe transient absorption with optical microscopy. Shot-to-shot subtraction of probe-only from pump-probe measurements is achieved by a fast mechanical chopper that blocks every other pump pulse (red). The signal is recorded in transmission and the probe is scanned across the focus with micrometer resolution.}