Abstract: The invention relates to a method for quantitatively and/or qualitatively detecting layer thicknesses of biological or chemical molecules by means of ellipsometric measurements. Said molecules are deposited on at least one metal layer by virtue of interactions with a gaseous or liquid medium, whereby said metal layer is provided with an immobilisation layer. A method that can be carried out quickly is provided by including the surface plasmon resonance. Said method is provided with a significantly greater detection sensitivity and can be used not only for qualitatively detecting layers. According to the inventive method, the angle of incidence and/or the frequency of the electromagnetic radiation which is used for the ellipsometric measurements is/are adjusted in such a way that a surface plasmon resonance is produced in the metal layer. The detection sensitivity (? cos ?)/(thickness of the layer to be detected) is adjusted by means of the thickness of the metal layer.

Abstract: The invention relates to a method for quantitatively and/or qualitatively detecting layer thicknesses of biological or chemical molecules by means of ellipsometric measurements. Said molecules are deposited on at least one metal layer by virtue of interactions with a gaseous or liquid medium, whereby said metal layer is provided with an immobilisation layer. A method that can be carried out quickly is provided by including the surface plasmon resonance. Said method is provided with a significantly greater detection sensitivity and can be used not only for qualitatively detecting layers. According to the inventive method, the angle of incidence and/or the frequency of the electromagnetic radiation which is used for the ellipsometric measurements is/are adjusted in such a way that a surface plasmon resonance is produced in the metal layer. The detection sensitivity (?cos?)/(thickness of the layer to be detected) is adjusted by means of the thickness of the metal layer.