1. A two-dimensional imaging surface plasmon resonance apparatus which comprises a sensor surface layer of a conductive material that can support a surface plasmon, a source of electromagnetic beams of two or more wavelengths that illuminate a two-dimensional surface area from either the front or the backside of the sensor surface layer, and a detector for simultaneous, or pseudo simultaneous, detection of two or more wavelengths of reflected intensities from the two-dimensional surface area, providing two or more two-dimensional images of the surface area, the two-dimensional images being a function of the effective refractive index at each point on the surface area.