Interferometer based on a surface-plasmon resonance for sensor applications

An interferometric method was used for the first time to detect, under surface-plasmon resonance conditions, phase changes in a reflected beam caused by changes in the refractive index of the medium being diagnosed. The threshold of the sensitivity to changes in the refractive index was estimated to be 4 × 10^–8. The proposed interferometer can be used successfully in bio and chemical-sensor systems.