INTERFERENCE IN FAR-FIELD RADIATION OF 2 CONTRA-PROPAGATING SURFACE-PLASMON POLARITONS IN THE KRETCHMANN CONFIGURATION

Work on experimental and theoretical study of interference of two cont ra-propagating surface plasmon polaritons is reported. In the experime nts, the technique of attenuated total reflection in the Kretschmann c onfiguration is used to launch the plasmon polariton on the surface of a thin silver film (similar to 500 Angstrom in thickness), which cove rs the flat surface of a semicylindrical prism of optical glass. A mir ror is used to send back the reflected light beam to the same area of the film. The reflected beam from the mirror launches another surface plasmon polariton in the direction opposite to the first surface plasm on polariton. Light beam from a He-Ne laser is used in the experiments . Noncoherent light from a monochromator is also used to help alignmen t. An interference pattern of the two surface plasmon polaritons is ob served and is recorded with an optical microscope located in the air s ide near the film. The above device is also described theoretically wi th numerical calculations of interference fringe spacing. (C) 1998 Ame rican Vacuum Society.