Scanning near-field optical microscopy with a free electron laser: application in material science and biology

Abstract

We present results obtained by a combination of spectroscopy, with infrared radiation emitted by a free electron laser, and a scanning near field optical microscope (SNOM) to investigate the local optical properties of material science and biological samples. The reflectivity in the SNOM images revealed features that were not present in the corresponding shear-force (topology) images and which were due to localized changes in the bulk properties of the sample. The size of the smallest detected features clearly demonstrated that near-field conditions were reached: an optical spatial resolution well below λ/15 was observed.