Structure of an edge-dislocation wave originating in plane-wave diffraction by a half-plane

A new treatment of the well-known Sommerfeld solution of the problem of pla ne-wave diffraction from a perfectly conducting half-plane is reported. We show, in both theory and experiment, that the diffraction field (E-polariza tion) can be represented as a superposition of real physically existing wav es, in contrast to geometrical and boundary waves postulated in Sommerfeld' s representation. Our representation includes two pairs of wave components: one pair propagates along the direction of the incident wave, and the othe r in a mirror-reflected direction. Each wave pair consists of a plane-wave component with an amplitude half that of the incident wave and a nearly pla ne-wave component with an infinitely extended edge dislocation. On the basi s of the proposed interpretation, all features of the half-plane diffractio n are explained. (C) 2000 Optical Society of America [S0740-3232(00)02512-6 ] OCIS code: 050.1960.