Using a vibrating opaque metallic tip, which periodically and locally modif ies the electromagnetic f ield distribution of a diffraction spot focused onto a sample surface through a microscope objective lens, we have observed optical resolution better than the diffraction limit both with topographical features and with purely optical ones. This procedure… (More)
Numerical simulations and experimental measurements to plasmon resonances in Ag Bowtie nanoantennas show that, as the bow angle increases, one fundamental resonance blue- and then red shifts; two types of high-order resonances emerge at large angles.
In coherent homodyne apertureless scanning near-field optical microscopy (ASNOM) the background field cannot be fully suppressed because of the interference between the different collected fields, making the images difficult to interpret. We show that implementing the heterodyne version of ASNOM allows one to overcome this issue. We present a comparison… (More)
The effects of tightly focused, higher-order laser beams on the photoinduced molecular migration and surface deformations in azobenzene polymer films are investigated. We demonstrate that the surface relief is principally triggered by longitudinal fields, i.e., electric fields polarized along the optical axis of the focused beam. Our findings can be… (More)
Excitation électrique de plasmons de surface avec un microscope à effet tunnel Soutenue le 18 juillet 2012 devant le jury composé de :
Heterodyne detection for apertureless near-field scanning optical microscopy was used to study periodic gold nanowell arrays. Optical near-field amplitude and phase signals were obtained simultaneously with the topography of the gold nanowells and with different polarizations. Theoretical calculations of the near-fields were consistent with the experiments;… (More)