On Mon, Mar 26, 2012 at 5:57 PM, David Roberson <dlrober...@aol.com> wrote: > Interesting information Xavier. The high Q nature of the resonances > suggests that the circulating plasmon currents may not be subject to > significant resistive losses. Is it possible that these currents are > flowing within a super conductive structure?
I personally wouldn't call plasmonic resonances "high Q", but I guess it depends on who you ask... they're many orders of magnitude less than a whispering gallery or fabry perot resonances. As for superconductivity, there's none of that going on. A plasmon is a quantized oscillation of free charge on the surface of a metal. This works the same way as signals in any electronic circuit: the electrons themselves aren't moving (except for a very slow drift velocity), but they transfer EMF at (nearly) the speed of light. I should also say that plasmons are polaritions in that they are coupled with the photon that creates them. I'm not so familiar with spheres themselves, but I know that on, for example, a flat silver film the 1/e lifetime of a plasmon is something like 100um, at which point it will either decay back into a photon or be absorbed as heat (resistive losses). > I would expect large spheres > of these types of material to be subject to standard resistive losses that > would broaden any resonance that appears due to size and shape. Are you > aware of any transition effects that occur as the size of the particle is > reduced? Yes... argh but I can't remember. A couple of weeks ago I attended a lecture about gold nanoparticles and I remember something significant happening around 80nm, but I can't say more. Basically since the plasmon is confined to the 2D surface of the sphere there are certain eigenmodes which can be excited. But at this point I don't think you can think of their behavior in the context of standard resistive losses. If you look up pictures of metal nanoparticles in suspension you can see that their size gives you different colors. > An example would be the appearance of highly sharpened spectral > line resonances which shows up as the size of the nanoparticle is > significantly reduced. An effect like this would imply that the atoms > within the nano sized structure are acting in a manner somewhat as a high > temperature condensate. Plasmons are oscillations of *free* electrons, which aren't bound to the atom. So no condensate here. Actually, for a condensate you need neutral atoms like Rubidium or Cesium. > Can anyone compare the line resonances seen in the nanoparticles to the line > resonances associated with atomic responses? I am particularly curious > about the bandwidth of the resonances about their center frequencies. Just throwing out numbers here... your run of the mill HeNe has a linewidth in the GHz, and that's assocated with an atomic transition. That's pretty big, but you can buy single mode atomic CW sources that are in the neighborhood of kHz. This is much sharper than nanoparticles, which I think are all in the tens of THz > >> Also, it would be interesting to see if the individual nano scale plasmon >> resonances would magnetically couple and thus share energy. > > I've seen this with nanorod arrays, where plasmon resonance couple to > each other, but I'm pretty sure it's not magnetic coupling (plasmons > are TM waves). > >> In the same >> line of thought, would this form of coupling tend to smooth out what would >> otherwise be very precise energy levels? > > I think you still get very sharp linewidths, even with coupling. > >> Dave >> >> -----Original Message----- >> From: Peter Gluck <peter.gl...@gmail.com> >> To: VORTEX <vortex-l@eskimo.com> >> Sent: Thu, Mar 22, 2012 6:34 am >> Subject: [Vo]:nanoparticles in LENR >> >> Quantum Plasmons Demonstrated in Atomic-Scale Nanoparticles >> http://www.sciencedaily.com/releases/2012/03/120321143017.htm >> >> This can be important for LENR >> >> Peter >> >> PS I cannot solve my "Chrome kills hyperlinks" problem- very bad >> for my blog, I can only by-pass it by using Internet Explorer >> Do you have some experience with it? >> -- >> Dr. Peter Gluck >> Cluj, Romania >> http://egooutpeters.blogspot.com >> >
