Ultrafast transient absorption spectroscopy based on supercontinuum generation with non-linear photonic crystal fiber

Abstract

We present a transient absorption setup based on a low-power laser system and a photonic crystal fiber for supercontinuum generation. The setup employs an ultrafast erbium-doped fiber laser system that emits at 775 nm with 80 MHz repetition rate which pumps a non-linear photonic crystal fiber that provides a supercontinuum in the NIR/VIS wavelength region for probing. By using an acousto optic modulator for pump-beam modulation and a lock-in amplifier we were able to achieve a detection-limit of 1 µOD. The setup reveals the potential of photonic crystal fibers as broadband sources in combination with low-power lasers.