Near-field microscopy study of propagation and focusing of designer´s surface plasmons polaritons at mid-infrared wavelength

Scattering-type near-field optical microscopy (sNSOM) allows one to map the propagation of purely evanescent waves such as surface plasmons polaritons (SPPs). We have recently used it to image SPPs generated electrically at the surface of a mid-infrared (MIR) quantum cascade laser (QCL) including all the building blocks for an integrated active plasmonic device. This talk will report on sNSOM observations on our new generation of integrated active plasmonic devices operating in the MIR, in which SPPs are launched on a metallic waveguide at distances of several hundred of micrometers from the end facet of a QCL.