Optical Lightguides Narrower then the Wavelength of Light
January 18th, 2006 | No Comments »I have written about this before but in conjunction with my recurring use of the term “nanowire” this reference may bear repeating. A paper in Nature (http://www.news.harvard.edu/gazette/2004/01.08/09-nanoeye.html) authored by a Harvard University group led by Mazur and Tong has recently found that when a fiberoptic lightguide is reduced in diameter to dimensions less than light wavelength (i.e., less than ~0.5 micron of 500 nm), instead of being transmitted through the interior of the guide, light flows around (or on the “outside of”) the guide itself. They further find that the more the diameter of the guide is reduced the more light flows outside of the guide.
The diameter of retinal receptors approximates (or is even less than) the wavelength of visible light. The historic and extensive research in the vision science field that modeled retinal receptors as lightguides, i.e., considering that light flowed internally within the guide, did not anticipate this behavior.
It is my belief that this new result exactly validates my hypothesis..i.e., that light interaction is between and not “within” retinal receptors! Further, the linkage between the evanescent wave nature of this light corresponding to the transverse dichroic orientation of retinal pigment further substantiates my claim.
I add a quote from the Mazur/Tong paper: “The nanowires carry light via evanescent waves that envelop the slender filaments. If two of the wires touch, light can jump directly from one to the other, something that’s not possible with conventional fiber optics.”
GCH
