Two adjacent surfaces separated by a small gap that allow tunneling of evanescent waves can exhibit a form of this phenomenon in a "frustrated" (*) variant.
The Hagen-Rubens relation connects this phenomenon in the infrared region to conductivity in metals. For sound intensity, the directivity factor is a correction that accounts for surfaces exhibiting this phenomenon. Two adjacent surfaces separated by a small gap that allow tunneling of evanescent waves can exhibit a form of this phenomenon in a "frustrated" (*) variant. This phenomenon does not occur for one polarization state at Brewster's angle. The inverse-sine of the ratio of two refractive indices gives the critical angle for the "total internal" type of this phenomenon. For 10 points, name this phenomenon in which a ray of light bounces off a surface at an angle equal to the angle of incidence.
The Hagen-Rubens relation connects this phenomenon in the infrared region to conductivity in metals.
reflection [or emissivity until "correction" is read; or total internal reflection or TIR after "tunneling" is read]