摘要 |
A long range SPR sensor comprises: (a) a source (4) of electromagnetic radiation, (b) an optical structure comprising a block (1) of material transparent to said electromagnetic radiation, a spacer layer (11) of dielectric material, a metallic layer (2) and a sensitive layer (3) capable of reaction with a sample to be tested, and (c) means (7) for monitoring radiation from the source (4) which is incident upon the block (1) and which is internally reflected at the interface between the block (1) and the spacer layer (11). A thin layer of dielectric material (12) of high refractive index is interposed between the metallic layer (2) and the layer of sensitive material (3). The provision of the thin layer of dielectric material (12) between the metal layer (2) and the sample under test enables the advantages of long range SPR to be more fully realised, notably a very sharp resonance with corresponding improvements in sensitivity. |