Light propagation in a porous silicon waveguide: an optical modes analysis in near-field

Abstract : We report on the first near‐field observation of light propagation in a porous silicon planar waveguide. The observation has been made possible using a scattering‐type scanning near field optical microscope (s‐SNOM). Optical constants of the propating modes are retrieved by two methods first, from the intensity profile and then from the complex field profile, the latter being obtained with a heterodyne interferometric setup.