plasmonresonanssia

Plasmonresonanssia, often referred to as surface plasmon resonance (SPR) in English, is a phenomenon that occurs at the interface between a metal and a dielectric material when incident light interacts with the free electrons in the metal. This interaction can excite collective oscillations of these electrons, known as surface plasmons. When the frequency of the incident light matches the natural oscillation frequency of the surface plasmons, a strong absorption of light occurs, leading to a sharp decrease in the reflected light intensity. This condition is known as resonance.

The resonance condition is highly sensitive to the properties of the interface, including the refractive index of the dielectric medium adjacent to the metal surface. Even very small changes in the local refractive index can cause a detectable shift in the resonance angle or wavelength. This sensitivity makes plasmonresonanssia a valuable tool for sensing applications. In a typical SPR sensor, a thin metal film, often gold or silver, is deposited on a transparent substrate. When molecules bind to the metal surface, they alter the local refractive index, which is then detected as a change in the SPR signal.

SPR spectroscopy is widely used in various fields, including biochemistry, pharmaceuticals, and environmental monitoring. It allows for the label-free detection and quantification of biomolecular interactions, such as protein-ligand binding, antibody-antigen interactions, and DNA hybridization. The technique's ability to monitor binding events in real-time without the need for fluorescent or radioactive labels makes it a powerful and versatile analytical method. The term plasmonresonanssia directly translates to "plasmon resonance" in Finnish and is commonly used in Finnish scientific literature.