Optical techniques for pump-probe magnetic measurements and nanoimaging of biological samples

Fast pump-probe magneto-optic techniques have been used to investigate the hot carrier and magnetization dynamics in InAs nanostructures deposited on GaAs(001). From these time resolved reflectivity and Faraday rotation measurements, different dynamics responses were found for samples containing different InAs thicknesses. We also present some results of near field spectroscopy with infrared radiation emitted by a free electron laser to investigate biological samples. The local reflectivity revealed features as a function of photon energy that were not present in the corresponding shear-force (topology) images and were due to localized changes in the bulk properties of the sample.