Read thru this preprint and although much of it is beyond my understanding, there are 2 things that came to mind.
1. the constant use of the terms cavity, and downconverting, and beat-frequency (in the Mhz range mind you!) implies behavior akin to RF/microwave engineering: Thus, perhaps one should look at the NAEs as simply waveguides, or resonant cavities. Thus, anywhere you had closely spaced parallel (physical) fractures within the Ni or Pd, and close to the surface (oriented normal to the Ni or Pd surface?), you have the conditions for an NAE; obviously packed with H or D. OR, nanotubes could easily act as extremely small waveguides, so the idea of using nanotubes could be an important key in getting higher output power. Has anyone ever asked Rossi if he makes use of nanotubes? Not that I would expect a straight answer. Start looking at how microwave/millimeter waveguides behave and what kind of phenomena occur in these structures, and apply the rules but only on a much smaller scale. so you're down to much smaller wavelengths. Can the downconverting occur over so many orders of magnitude as to facilitate, or even gamma-to-thermal conversion? How many gamma wavelengths fit into the phonon wavelength? Or, more poetically, how many gammas can you fit on the head of a phonon? 2. page 5, last paragraph: "These regenerative oscillations are formed between the competing phonon and free carrier populations, with slow *thermal* red-shifts (~ 10 ns timescales) and fast *free-carrier plasma* dispersion blue-shifts (~ 200 ps timescales) in the case of our graphene-silicon cavities." 'Regenerative oscillations formed between'. physically between? Those oscillations are formed physically between 'competing' thermal (phonon) and free-carrier (electron) elements (populations). 'competing' phonon and free-carrier populations. competing for what? Physical space in which to oscillate? -Mark Iverson From: MarkI-ZeroPoint [mailto:[email protected]] Sent: Sunday, July 15, 2012 3:09 PM To: [email protected] Subject: [Vo]:YAGS: Yet Another Graphene Surprise... FYI: "With the placement of a sheet of graphene just one-carbon-atom-thick, the researchers transformed the originally passive device into an active one that generated microwave photonic signals and performed parametric wavelength conversion at telecommunication wavelengths." http://phys.org/news/2012-07-ultralow-power-optical-frequency-graphene-silic on-photonic.html http://arxiv.org/pdf/1205.4333v4.pdf "They have engineered a graphene-silicon device whose optical nonlinearity enables the system parameters (such as transmittance and wavelength conversion) to change with the input power level. The researchers also were able to observe that, by optically driving the electronic and thermal response in the silicon chip, they could generate a radio frequency carrier on top of the transmitted laser beam and control its modulation with the laser intensity and color. Using different optical frequencies to tune the radio frequency, they found that the graphene-silicon hybrid chip achieved radio frequency generation with a resonant quality factor more than 50 times lower than what other scientists have achieved in silicon." Haven't read the preprint yet, but if I understand this correctly, they are claiming that a passive sheet of graphene can behave as an active (electronic) device. passive devices are those which do not require a separate power source (resistors, capacitors, inductors). Active devices, like transistors, require a power source. My guess before reading the article is that the power source here is simply a laser or some other form of energy which is getting converted (or downshifted) to some other form. Also, the statement, "achieved radio frequency generation with a resonant quality factor more than 50 times lower" must be a typo. a lower Q-factor is not something to write home about! -Mark
