Local Optical Field in the Neighborhood of Structured Surfaces: Phase Singularities and Talbot Effect
B. Levine, M. Caumont, C. Amien, B. Chaudret, B. Dwir and W.S. Bacsa
LPST Université Paul Sabatier, FR
Keywords: local optical field, structured surfaces, middle field, Talbot effect, phase singularities
We have probed the local optical field in the vicinity of structured surfaces to observe optical coherence effects. We have used a sub -wavelength sized optical fiber probe to map the local field of microgratings and nanometer sized gold particles. While probing the middle field region, the ratio of the aperture size to the object-probe distance is smaller (a/h =1) than in the nearfield region (a/h=10). In the middle field one probes mostly the transverse field component and probe induced effects are reduced. We have observed self-imaging (Talbot effect) of the micrograting structure in the direction of the incident beam and apparent phase singularities from the deposited gold particles in the direction of the reflected beam.
Nanotech 2004 Conference Technical Program Abstract