[extropy-chat] Suicide the Green way

Tue Nov 21 18:53:49 UTC 2006

On Tue, Nov 21, 2006 at 11:21:00AM -0500, Robert Bradbury wrote:
> 
>    On 11/21/06, spike <[1]spike66 at comcast.net> wrote:
> 
>      Robert, it's from Maxwell's equations.  Recall that when a material
>      reflects a photon, the photon induces a circular magnetic field in
>      the material.  In general better conductors make better reflectors.
>      [snip]

We have to be careful, when we reduce to what are actually quantum
phenomena to macroscale approximations, which are frequently invalid.

If you look at reflectance spectra of various mirror metals
on http://www.kruschwitz.com/HR's.htm you'll see that approximations
designed for classical optics, they can only take you that far.

Also, careful with nanohole arrays, these things can misfire:
http://flux.aps.org/meetings/YR04/MAR04/baps/abs/S3560.html

[J36.001] Transmission properties of an array of sub-wavelength holes in a metal film
Kwangje Woo, Sinan Selcuk, Arthur F. Hebard, David B. Tanner (Department of Physics, University of Florida, Gainesville, FL 32611)

It is known that the intensity of light transmitted through an array of holes, which are of sub-wavelength scale, can be surprisingly high at certain wavelengths. The enhanced transmission is attributed to a coupling of surface plasmons on the two sides of the film. We have measured the transmission of an array of holes on a metal film that is sandwiched between two different dielectric materials. With this measurement we have analyzed the effects of metal-dielectric interfaces in transmission spectra. For example, in a sample with air-metal-fused quartz structure we have found that the surface plasmon modes of the quartz-metal interface are more dominant in the transmission spectrum than those of the air-metal interface. The transmittance at the surface-plasmon peak can be as high as 40%, about twice the open area of the hole array. The effect of different film thicknesses, different materials, the dependence on light polarization, and the dependence on the parameters of the hole array will be discussed.

...

[J36.003] Single nanohole as a point source of the surface plasmons
L. Yin, V. Vlasko-Vlasov, A. Rydh, J. Pearson, U Welp, S.K. Gray (Argonne National Laboratory), S.-H. Chung (Northwestern University), G.C. Schatz (Affiliation), D.E. Brown, C.W. Kimball (Northern Illinois University)

It is found experimentally that subwavelength holes in thin metal films serve as point sources of the surface plasmon polaritons. Near Field Scanning optical microscope is used for imaging light patterns around individual nanoholes made by FIB in gold and silver films. The intensity distributions around the holes are qualitatively explained accounting for the interference between surface plasmons and attenuated transmitted wave. These results are supported by exact 3D finite-difference time-domain numerical simulations. The effect of the metal coated tip on the light pattern is explicitly accounted for and it is shown that the measured signal is correctly presenting the surface plasmon fields around the hole. It is also shown that the light pattern near the hole can be manipulated by the conditions of illumination and the choice of metal.

etc.

Not to forget the simple tensile stress of a gossamer assembly, pulling 
a kg-payload with many g's. Carbon nanotube ropes and (truss?) cloth appears about optimal
here, whether metallized with membranes across mesh gaps, or not.

>    I strongly suspected that someday someone would come up with a good
>    reason for me to go back to school... :-(

Going back to school needs a reason?

-- 
Eugen* Leitl <a href="http://leitl.org">leitl</a> http://leitl.org
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