Light slows down when it enters a medium such as glass or water, and its new speed depends on the material. However, researchers now calculate that they can control the speed of light in a new way. They found that a series of metal strips, with gaps between them, can act somewhat like a uniform slab of glass, except that the speed of light depends on the dimensions of the strips rather than on the material. By narrowing the gaps, they propose making a structure that slows light much more than any conventional material can. Such structures could help make tiny optical or optoelectronic devices both smaller and more efficient.
The speed of light traveling through a metal "Venetian blind" is fixed by the size of the gaps, not by the material, according to calculations, which might be useful for optical devices. In the "waveguide" mode, light travels along the blind (top, vertical lines show fields in gaps) and creates almost the same external magnetic fields generated by light traveling through a transparent slab with a very low light speed (bottom).
Image Credit: Phys. Rev. Lett. 94, 197401 (2005)
Read more about this research at Physical Review Focus.
Text courtesy of Physical Review Focus