Abstract

Surface plasmon polaritions are surface-bound longitudinal charge density oscillations in the electrons of a solid It is well known that these excitations may be stimulated by light incident on a grating profiled metallic medium. The grating imparts momentum to the incident electromagnetic wave, thus accommodating simultaneous matching of energy and momentum between the field and the polariton mode, further, such coupling can take place over the entire energy range of the mode, which extends from near zero to the asymptotic surface plasmon energy, determined by the density of free charge carriers in the medium .In this work the angle of incidence is fixed and the incident photon energy is varied. As the energy scans across the coupling condition a pronounced dip in the reflectance is produced. We show this effect, for Ag in the visible region and for YBCO in the far-IR, in the calculated reflectance curves below

© 1996 IEEE