I understand! I understand! Thanks for a wonderful explanation, with the conceptual material so well presented before even a breath of mathematics. You are a wonderful teacher!
Bose-Einstein statistic cannot be applied on electrons, since they are fermions. I guess it was just a momentary black out. Otherwise, very nice explanation.
The Figure with the two spheres is super confusing. It almost looks like the distance between the NPs must be 1/2 wavelength. But thats not the case. The distance between the NPs are topic of plasmonic surface lattice resonances.
17:05 at plasma frequency, does the metal ‘absorb’ the energy and make energy loss? It looks that plasma frequency(ω_p) and LSPR frequency is quite different. It would be glad if I can get you answer. Thanks for the great lectures!
Nanogold seems to be very usefull for make the sunlicht wave lengths distribution (1300w/m2) mutch beter suited for the photon energy to ´translate´ to an electron push in the the solar cell p-n layer. Normally the photons sensesible materials work best only in relative small range of the available sun wave lengths By using nanogold the effeciency can be much higher of an photo cel by the `Surface Plasmons` effect of (nano)gold. It seems the first experimental solar panels based on this will be lanced in 2025
Erratum: As you said, Electrons are Fermions and they obey the Fermi Dirac Statistic and not the Bose Einstein Statistic. The graph that you have shown with the Fermi Energy was the one for Fermi Dirac but you were wrongfully talking about Bose Einstein. In the Bose Einstein Statistic, all particles can have the same ground state.
Why we call it as UV-Visible absorption spectra instead of extinction spectra? Why we tell absorption peak of nanoparticles instead of extinction peak..?
Is it me or is this array remind anyone of DNA and also Einstein's theory that light travels in a spiral???? And I believe he theorized that light also had a particle??
Im in my third year Nanoscience undergrad....and this is the best explanation I've found explaining surface plasmons compared to any research paper or notes I've read.
I'm not sure since I'm in photonics, but try any grad level text book that has like "Surface Plasmons and Nanophotonics" by Mark L. Brongersma, Pieter G. Kik
@@soumyaa4230 I'm not sure since I study photonics, and only briefly know LSPR and SPR, but you could try any grad level textbooks like "Surface Plasmons Nanophotonics" by Mark L. Brongersma, Pieter G. Kik
@@Scott-if3ce thank you so much for replying, I'll surely check out that book Actually I'm doing an internship on surface plasma wave induced higher harmonic generation on metal semiconductor interface It's my first time studying this topic So thank you again
This Is a great video the microphone hurts my ear slightly so i keep volume halfway all in all this is an absolutely awesome explanation I just started to learn about Plasmons and this is the tip of the iceberg Fermions really make more sense of it all now. Thank you for this lecture I have subscribed now.
Thanks Tonya for your valuable lecture, we scientists often miss the -read between the lines- information in technical books and your information regarding the physical picture at what happens inside the bulk and surface are really nice. The phase difference between incoming and radiated plasmon light can be understood due from the dispersion relation of the classically damped harmonic oscillator phase lag for high frequency (e.g. visibe light) and your explanation regarding quantum confinement of nanoparticles can also be understood from the particle in a box model I am sure you already know all this stuff and its always nice to see things from a physical picture framework as you explained.
Tonya, I think I am catching a bit of surface plasmon resonance but I was just curious as to what happens after absorption of the particular frequency or frequencies. Does this light energy transfer to actual motion of the particles, does it get dispersed as light but not directionally specific as the incident light and last, is the light we see from a nanoparticle the reflected light or is it light that travels straight through without reflection or refraction. Thanks, Dr. P. From Pratt Kansas
Hi this video is very useful. i would like to know how do you plot a SPR graph with reflectivity vs angle? As i have made a matlab program and generated graph. but i do not know how to plot a graph for reflectivity vs angle for different thickness?i hope to hear fromyou...thank you
"The electric field's oscillatory pattern causes a rippling wave pattern in the spatial distribution of the electrons. However, the response of the electrons is out of phase with the EM wave." I suppose then that our mirror image could not possible be a true reflection of ourselves. The light (EM waves) coming from us, is bounced back in an other form, the rippling in the metal iron gas sea which is out of phase. It's a violent and chaotic view of what our reality is supposed to be really. In a sense, the electron gas sea from the metal is in balance but stationary. The traveling EM radiation is also balanced but in motion. Then there's impact and the ripples of "the clash" travel back to our eyes. What kind of fucked up version then do we see in the mirror, compared to our true resonance?
Hello friends 🌹 I had a few questions, if anyone knows, thank you for your help 🙏 I am researching structures based on spoof surface plasmon polariton in the microwave regime. I would appreciate it if you help me...... I had three questions: 1- How can I prove that these structures work based on surface plasmon in cst?(What should I observe in the structure to prove this?) 2- What is the advantage of using these structures? Because we have a lot of similar structures without this corrugated part that they are smaller and simpler. 3- What diagrams do I need in cst to prove sspp? 4- What is a light line? Why assign a wave number to it? And do they measure with it? What are the ups and downs of the Light Line ? Why does up is PP and Down SPP? What is its formula? 5- How to find the formula of MS, SIW, CPW lines? can not find anything in it that the air line in leaky wave antennas becomes the same as the light line? Or are they different? If you have any books, articles or sources, thank you for introducing them
I'm not taking this class.. I graduated 20y ago in an entirely different field. But I still thought this video was interesting and explained something in a satisfactory way that has puzzled me for years.
I personally wouln't say that light is *absorbed* and re-emitted by the metallic surface, emission is a non-parametric process and also is completely random is phase, if light really was absorbed and re-emitted by metals, then they would *appear* to scatter the light just like a rough colourless crystal would, in all directions and appear white and exert diffuse reflection instead of clean reflection. Reflection is a parametric process and therefore depends on angle of incidence. It's an elastic scattering phenomenon and respects the laws of reflection, emission (namely spontaneous emission) does not. From wiki: " Light of frequencies below the plasma frequency is reflected by a material because the electrons in the material screen the electric field of the light. Light of frequencies above the plasma frequency is transmitted by a material because the electrons in the material cannot respond fast enough to screen it. In most metals, the plasma frequency is in the ultraviolet, making them shiny (reflective) in the visible range. Some metals, such as copper[4] and gold,[5] have electronic interband transitions in the visible range, whereby specific light energies (colors) are absorbed, yielding their distinct color. " It's well known that most metals are translucent to ultraviolet light.
Hmmm. I believe the answer is not necessarily. In a UV VIS spectrum, all it means is that the energy of that particular wavelength is absorbed by the material. This can be due to exciting a transition in the material that happens to have that energy, in addition to the SPR phenomenon. So it would depend on what material the nanoparticle is made of. You would have to make sure that there are no corresponding excitations in the bulk material at those energies, among other possibilities, before jumping to any conclusions. Hope that helps.
Fantastic Introductory and conceptual explanation of plasmons. Very nice and efficient compared to videos where the instructor sprays you with math and quantum physics (who themselves usually don't understand very well) prior to giving an intuitive and conceptual lecture. Thank you
What is the mechanism that causes the oscillating electrons to re-emit the energy as reflected light instead of hold on to it and continue to oscillate? (re: 9:39 in the video). Is this something analogous to stimulated emission / spontaneous emission when atoms absorb photons? Further, what determines the coherence of the outgoing wave wrt to the incoming wave (if it is even coherent at all?)
We have experienced Plasmonic mechanisms with semiconductive transition metal oxides on a mulligan insulator when in proximity to organic absorbers provides both bathochromic red shifts in the organic absorber and hyperchromicity that is extraordinary. Clearly the level of energy quantanized by exposure to light transfers the Plasmonic energy to the adjacent organic absorber to induce hyperchromicity effects. This industrial example is now utilized commercially to provide broad permanent absorption over a range of 200 to 800 nm and into the mid and far infrared region Therefore Plasmonic and Plasmonic effects are no longer limited by nanogold or nanosilver examples but rather among other more prevalent and far cheaper species yet to be discovered to date. Spectral enhancers that function by Plasmonic mechanisms clearly broaden those more expensive and fugitive organics with their own physical chemical limitations. Nice lecture but there is much more to be understood!
We have yet to fully grasp the full implications of the science ! When we think we know something we discover we knew nothing . We need to let knowledge come to us and not the other way around
She never said that gold and silver were the only materials that can have surface plasmons. They're commonly used in school laboratories, so a reasonable example to cite in a brief introductory lecture.
it's really good. i have one doubt i.e. how did you get different type of responses for different wavelengths? i mean , have you use any equation or coding?
great work and hope to continue you simple method of teaching and intense information confined with an easy water-like method of explanation!, keep it up :)
I'm confused. For metals, I thought the Fermi energy was the energy difference between the highest and lowest occupied single-particle states in a quantum system of non-interacting fermions at absolute zero temperature, with the lowest occupied state typically taken to mean the bottom of the conduction band.
Yes, that's right. On the slides, I say that "the electron's highest occupied energy state at absolute zero is the Fermi energy." Perhaps I could have been more specific and said "valence electrons" to differentiate between the electrons in the 1s state from the outermost shell, but that is a bit picky, as I was discussing the free electron sea at the time (which are valence electrons). So with that definition, take the lowest energy valence electrons and call that an energy of 0, and then the highest occupied states have the Fermi energy. This is at absolute zero. At higher temperatures, the distribution function is not cut off so sharply, and looks more rounded, and some electrons have energies higher than the Fermi.
