Abstract

It is well known that the optical properties of molecules are modified by nearby surfaces or structures. We demonstrate here a technique by which the fluorescent signal detected from a near-monolayer of molecules can be enhanced by a factor that can exceed 1000. The technique adds to the multilayered substrate geometry of a previous work¹ a periodic surface corrugation that produces directional, rather than nearly isotropic, fluorescent radiation. The directional nature of this emission also allows for polarization discrimination, since different polarization components are radiated preferentially into well-resolved angular directions. The technique we describe is of fundamental interest as an aspect of the dipole-surface problem; it is also potentially of practical importance to the biomedical/biochemical community as a sensitive and versatile diagnostic tool.

© 1992 Optical Society of America