Pump-probe micro-spectroscopy by means of an ultra-fast acousto-optics delay line

We demonstrate femtosecond pump-probe transient absorption spectroscopy using a programmable dispersive filter as an ultra-fast delay line. Combined with fast synchronous detection this delay line allows for recording of 6 ps decay traces at 34 kHz. With such acquisition speed we perform single point pump-probe spectroscopy on bulk samples in 80 $\mu$s and hyperspectral pump-probe imaging over a field of view of 100 $\mu$m in less than a second. The usability of the method is illustrated on a showcase experiment to image and discriminate two pigments in a mixture.