Evanescent waves

Evanescent wave applications

Electromagnetic evanescent waves have been used to exert optical radiation pressure on small particles to trap them for experimentation, or to cool them to very low temperatures, and to illuminate very small objects such as biological cells or single protein and DNA molecules for microscopy (as in the total internal reflection fluorescence microscope). The evanescent wave from an optical fiber can be used in a gas sensor, and evanescent waves figure in the infrared spectroscopy technique known as attenuated total reflectance. In x-ray and neutron grazing-incidence small-angle scattering, evanescent waves lead to strongly enhanced scattering from a thin layer (Yoneda peak), which can be used for calibration.