Kretchmann configuration

The Kretchmann configuration illustrated in Figure 3.8 relies on the phenomenon of total internal reflection. This process occurs when light traveling through an optically dense medium, e.g. glass, reaches an interface with a material of lower optical density, e.g. air, and is reflected back into the dense medium. Although the... 

Figure 3.8 Kretchmann configuration of a metal-coated prism used for surface plasmon resonance investigations of interfacial supramolecular assemblies...

Two arrangements of ATR optical prism couplers are used the Kretschmaim-type arrangement with a metallic film deposited directly onto the coupHng prism and the Otto-type arrangement with a metallic fihn separated from the coupling prism by air or other dielectric material of a thickness of about one wavelength of the radiation used in the experiments. The Kretchmann configuration is more convenient and is used in most applications. 

Figure 15.1. (A) Schematic of surface plasmon resonance based on Kretchmann configuration used in most of the commercial SPR instruments. (B) Typical sensorgram showing the binding of analyte with its immobilized ligand on the chip surface (association phase), separation of the two binding partners (dissociation phase), and, finally, regeneration of the surface.

The configuration most often used in SPR instruments relies on the phenomenon of total internal reflectance and was developed by Kretchmann (Fig. 8).71,73 Total internal reflectance occurs when light traveling from a medium of higher refractive index toward a medium of lower refractive index reaches the interface and is reflected back completely into the higher refractive index medium. An important side effect of total internal reflection is the propagation of an evanescent wave across the interface into the medium of lower refractive index. 

Wang, S. F., Chiu, M. H., Chang, R. S. (2006) Numerical simulation of a D-type optical fiber sensor based on the Kretchmann s configuration and heterodyne KAerferornsVcy. Sensors and Actuators B 114 120-126. 

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