Exterior Caustics Produced in Scattering of a Diagonally Incident Plane Wave by a Circular Cylinder: Semiclassical Scattering Theory Analysis

Rie use the semiclassical limit of electromagnetic wave scattering theory to determine the properties of the exterior caustics of a diagonally incident plane wave scattered by an infinitely long homogeneous dielectric circular cylinder in both the near zone and the far zone. The transmission caustic has an exterior/interior cusp transition as the tilt angle of the incident beam is increased, and each of the rainbow caustics has a far-zone rainbow/exterior cusp transition and an exterior/interior cusp transition as the incident beam tilt angle is increased. We experimentally observe and analyze both transitions of the first-order rainbow. We also compare the predictions of the semiclassical approximation with those of ray theory and exact electromagnetic wave scattering theory. (C) 2000 Optical Society of America [S0740-3232(00)01010-3]. OCIS codes: 080.1510, 290.4020.