SURFACE PLASMON DIFFRACTION BIOSENSOR
Abstract
We describe experiments with surface plasmon polaritons excited by a laser beam in the Kretschmann configuration that are diffracted by a periodic pattern at the metal/dielectric interface. This suggested technique has become a novel sensing principle with particular potential for bio-affinity studies. It is demonstrated that the optical field enhancements associated with the resonant excitation of surface plasmons directly translate into a sensitivity gain. A few characteristic features of the obtained diffraction patterns, e.g., the quadratic increase of the intensity diffracted into higher order spots with the increase of the grating amplitude, are discussed. Moreover, it is shown that the basic mechanism of the signal generation leads to a so-called self-referencing of the sensor which makes it largely insensitive to variations in temperature or refractive index fluctuations of the analyte solution.
