ABSTRACT
Surface plasmon spectroscopy (SPS) has matured into a rather widespread surface optical technique with numerous examples demonstrating its potential for interfacial studies and thin film characterization [1]. This gain in popularity originates, in part, also from the availability of commercial instruments [2] which helped to attract customers from new communities. Foremost, however, it was recognized that surface plasmons constitute an interfacial light source in an evanescent wave format that offers a number of advantages over complementary optical techniques, e.g., ellipsometry. Despite the high sensitivity of SPS for monitoring, on-line and in real time, small changes in the thickness of surface coatings, e.g., by adsorption/desorption processes, it is a relatively simple technique. Essentially, one needs a linearly polarized (laser) light source; a coupling element, typically a glass prism or a grating structure, both coated with a thin (noble) metal layer as an optical resonator and in contact to a measuring cell; and a photodetector module. Thickness changes in the angstrom range can be easily evaluated quantitatively with a time resolution (in extreme cases) down to nanoseconds [3]. For laterally heterogeneous thin film samples a spatial resolution-in a microscopic mode-of a few micrometers can be obtained [ 4].
