Brief and qualitative explanation of what a plasmon is physically. Plasmonics and surface plasmons are of increasing interest for controlling light propagation in materials and nano-optical device engineering.
At lower frequencies, the damping is severe enough so that the electron kinetic energy no longer will play a role, so the response will be purely magnetic (as you say, caused by charge motion) and electric (as you say, caused by charge separation). At low enough frequencies, the mass of the charge carrier should play a role, as a heavier mass would result in reduced magnetic and electric response, due to reduced amplitude and speed of motion.
At frequencies far below the plasma frequency, am I right to assume that a mechanical wave can propagate through the electrons of a plasma? And the energy will alternate mainly between electrostatic (caused by charge separation) and magnetic (caused by electron velocity)? The electron mass is not important when the accelerations are small but the inertia comes from the need for the electron to build a magnetic field. Thank you.
Like in spintronics, we can induce magentic properties to a non-magnetic material using electrons from an external source and vice-versa, can we induce plasmonics to non-metallic particles ?
why s= cube root of inverse particle density ?? i dont really grasp this point :( anyone can tell me why? I basically calculate the distance s based on the calculating cube volume formula. If so the derived s is different from that mentioned in the video
Hi Karl, thanks for the video. Would you happen to know where I can find more information on how plasmons help us confine light to sub-nanometer scales and further how this helps us design novel nano-photonics devices? I’m in the process of deciding what I want to focus on when I apply to graduate school next fall and nano-photonics are my primary interest :) Thank you, Frank
Is guessing the electron charge really an adequate move if we want an exact mathematical calculation? It's not a truly harmonic oscillator, when the force is not proportional to the separation as it should be. What if it were? What then?
you're right of course. this treatment isn't rigorous in that it does not clearly state the approximations it makes, nor does it derive a complete result within the context of those (unstated) approximations. You are very reasonably asking for more--I would start looking in graduate-level E&M texts for that, although resources might alsobe available online nowadays.
hi, can you explain to me why plasmons are quasi-particle? Also is it possible for a surface plasmon to interact with a plasmon present inside the solid?
arup paul Sorry, not sure I can help very much. To my thinking, a particle in the same way a photon is a particle--in reality it is an excitation of an electro-mechano-magnetic mode, and so it's not really a simple particle. For a more rigorous answer, I think you'd need to talk to a condensed-matter physicist! not me.
Polaritons also a quasipartle that is produced when plasmons and em wave (photon) interacts/couples each other, usually strong interaction between them.
Hello Mr Berggren! Why do the the electrons osscilate inside a solid, I don't unterstand this, has it something to do with the uncertainty principle? Of course they move because of there kinetic energy, as a quasi-free particle but how can you explain the instability of the equilibrium state of the electrons? In my opinion those oscilaltions should come the a rest as time goes on (in a completly isolated solid) or am I wrong?
Theleviathan You're right! The oscillations only occur in the presence of some excitation (e.g. an applied electric field). Thermal energy can cause momentary excitations. In all these cases, the oscillation quickly dampens and disappears.
Thank you for the answer! I've recently read of the Bethe-Formula discribing transport of ions through a solid. In this formula shows up a so called "mean ionization energy". In the explaination they talk about "density fluctuations" of the electrons s.c. "Plasmons". I can accept that from a quantummechanical point of view, but in a classical way this Plasmons are oscillations too, or? (without external electric field?)
Theleviathan Not sure i understand the question fully... from a classical point of view, at zero temperature without an excitation (e.g. external input of energy via a driving field or some motion of the surrounding lattice) of course there would be no oscillation. But the oscillatory mode is there, so if something is added to drive it (e.g. temperature, field, etc.), it can oscillate.
Hello, is it possible, that the electron oscillation can occur because of the light? i suppose that's the basic rule of surface plasmon resonance, but I want to be sure, that fotons cause those changes... ps. the video is great
A very late comment. If there is an applied (incident) EM wave and the frequency of EM wave is lower than the plasma frequency, how can we proof/derive that this EM wave will be reflected by using Newton's 2nd law or Maxwell Equation? Dielectric constant when applied frequency < plasma frequency will be negative by using equation, dielectric constant = 1 - w_p^2/w^2. How is this tell us that the EM wave will be reflected?
thank you.if i can understand lacing nano material on metal will create a compling of the electron and the static field? i am a builder congnitive thinker a amateur in science terms.can you explain are help me create a language so we can build better nano devices.i am also the discoverer of the tube cells made with water and nano material for a ever lasting batterie.like a cristal cell but much easy to build. i sure need expert guidance and support if we to make this a true advanced d.i.y heaven.loll contact me pls on fb.
