Extraordinary Optical Transmission

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Interference pattern of double slits, where the slitwidth is three times less the wavelength.

Extraordinary Optical Transmission (or EOT as it has come to be known) is an optical phenomenon that happens in slits that are narrower than the wavelength of the light. Generally when light falls on such a slit, it emerges having been diffracted isotropically, ie it scatters in all directions evenly. However, if instead the slit is surrounded by highly patterned grooves, a highly directional beam emerges instead of the diffracted & isotropic beam. This is called an Extraordinary Optical Transmission.

This phenomenon is attributed to the presence of surface plasmon resonances and constructive interference. A surface plasmon (SP) is a collective excitation of the electrons at the junction between a conductor and an insulator and is one of a series of interactions between light and a metal surface called Plasmonics.

[edit] Applications

EOT is expected to play an important role in the creation of components of 'photonic' circuits. (Photonic circuits are analogous to electronic circuits.)

[edit] References

Ebbesen, T. W.; Ghaemi, H. F.; Thio, Tineke; Grupp, D. E.; Lezec, H. J, "Extraordinary Optical Transmission through Sub-wavelength Hole Arrays", APS 1998, http://adsabs.harvard.edu/abs/1998APS..MAR.S1511E