Enhanced Surface Plasmon Resonance method

摘要

The disclosure relates to processing SPR signals, in particular signals obtained by illuminating a conductive surface with light at two wavelengths. Processing SPR signals can involve processing a first and second signal indicative of an intensity of light, received from a conductive layer at which SPR has occurred, as a function of angle of incidence, reflection or diffraction at the layer. The first and second signals each have two dips corresponding to a respective wavelength of the light at a respective angle at which surface plasmon resonance occurs for the respective wavelength and a peak between the two dips. The processing includes deriving a first and second value of a quantity indicative of signal magnitudes in the region of the peak. The first and second values can be compared to detect a change in refractive index at the layer after the first signal and before the second signal was captured.

主权项

1. A system for detecting a change in refractive index, the system comprising:
a light source arrangement for simultaneously illuminating a conductive layer with light at two wavelengths; a detector arrangement for measuring an intensity of light returned from the conductive surface at angles lying between an angle at which a first intensity minimum due to Surface Plasmon Resonance at one of the wavelengths occurs and an angle at which a second intensity minimum due to Surface Plasmon Resonance at the other one of the wavelengths occurs; and a processor for detecting a change in the refractive index at the conductive layer by detecting a change in the measured intensity, wherein the processor is arranged to implement a method comprising:
processing a first signal indicative of an intensity of light, received from the conductive layer at which SPR has occurred, as a function of angle of incidence, reflection or diffraction at the layer, the first signal having two dips corresponding to a respective wavelength of the light at a respective angle at which surface plasmon resonance occurs for the respective wavelength and a peak between the two dips, wherein the processing includes deriving a first value of a quantity indicative of signal magnitude in the region of the peak;processing a second signal indicative of an intensity of light, received from the conductive layer at which SPR has occurred, as a function of angle of incidence, reflection or diffraction at the layer, the second signal having two dips corresponding to a respective wavelength of the light at a respective angle at which surface plasmon resonance occurs for the respective wavelength and a peak between the two dips, wherein the processing includes deriving a second value of a quantity indicative of signal magnitude in the region of the peak; andcomparing the first and second values to detect a change in refractive index at the conductive layer after the first signal and before the second signal was captured.