SPR (Surface Plasmon Resonance)

SPR is the resonant excitation of collective oscillations of free electrons (surface plasmons) at the boundary of a thin metal layer and a dielectric, driven by incident light.

How does surface plasmon resonance work?

Resonance occurs at a precisely defined angle of incidence or wavelength of light, strongly dependent on the refractive index of the material directly adjacent to the metal layer (usually gold or silver). Even a small change in that index — e.g. caused by a biological molecule binding at the sensor surface — produces a measurable shift in the resonance condition.

Applications

SPR is the basis for biochemical sensors that detect, in real time, the binding of proteins, DNA, and other molecules without fluorescent labeling, widely used in pharmaceutical research, medical diagnostics, and environmental monitoring.

Related terms

Plasmonics

LPG

FDTD