OPTICAL SENSING DEVICE COMPRISING A FINITE WIDTH STRIP FOR PROPAGATING A PLASMON-POLARITION WAVE

摘要

An optical device has a waveguide structure comprising a thin strip (12) having finite width and thickness of material having a relatively high free charge carrier density supported by a membrane (14) having a predetermined thickness of material that has a relatively low free charge carrier density. The dimensions of the width and thickness of the strip and the thickness of the supporting membrane are such that, when the waveguide structure is surrounded at least partially by an environment (E) having a low free charge carrier density, optical radiation having a wavelength in a predetermined range couples to the waveguide structure and propagates along the length thereof as a plasmon-polariton wave that permeates at least part of the environment (E).