Two-dimensional optics with surface electromagnetic waves

Abstract

Two-dimensional optical effects were observed for surface electromagnetic waves (SEW) on metals at lambda = 3.55 cm. Refractive processes with prisms and lenses established Snell's law experimentally. Reflection with prisms and metal sheets established the law of reflection and indicated that radiative losses were small and that Fresnel's equations hold to a good approximation for the reflectivities of SEW. A two-dimensional SEW grating was made and first-order diffraction observed. Although the experiments were performed at microwave frequencies, the principles are usable for two-dimensional SEW optics at least as far as the near ir. It was shown that the propagation constant of the SEW with an overlayer material is as though the SEW propagates entirely in the overlayer material. That is, losses in the metal substrate were negligible.