A broadband Kerr shutter for femtosecond fluorescence spectroscopy

An improved Kerr-based set-up for time-resolved emission spectroscopy in the ferntosecond regime is presented. The Kerr gate is switched by ferntosecond NIR pulses of similar to1100 nm. Thereby, practically no background emission of the Kerr medium is observed for wavelengths smaller than 1000 nm. This allows for the simultaneous acquisition of emission spectra in the spectral range from 350 nm to 1000 nm. By employing mainly reflective optics, the dispersion of the gate set-up could be kept below 0.2 ps (500-800 nm). The time resolution of the set-up was similar to100 fs. Its performance is demonstrated by recording the spectro-temporal behaviour of a white-light continuum and of the fluorescence emissions of beta-carotene and an azobenzene derivative.