Around slide 3, I called the statistics governing the model of conduction Bose-Einstein statistics. Of course they are Fermi-Dirac statistics. I think it was sleep deprivation, sorry about that.
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!
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.
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
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 :)
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
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?
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.
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
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.
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.
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.
Thanks for sharing this lecture! I've just started my PhD on plasmonic catalysis with absolutely no theoretical knowledge about it, after watching your video it all makes sense now :)
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?)
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
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!
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.
Why we call it as UV-Visible absorption spectra instead of extinction spectra? Why we tell absorption peak of nanoparticles instead of extinction peak..?
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 enjoyed your lecture very much. Even if it doesn't meant to, it kinda explains the nature of refractive index. What I am puzzled with though is that how (if at all) the resonance might be affected with the polarization of incident EM wave.
According to the theory, surface plasmons can only be excited by field components that match the parallel wave vectors. If you think about a small, spherical nanoparticle suspended in a liquid, no matter how you orient the incoming wave, there will be a part of the sphere that has a parallel component to it. So the plasmon would still be excited. If you look at this link: www.photonics.ethz.ch/fileadmin/user_upload/Courses/NanoOptics/plasmonss.pdf there is a section that describes what happens for a small spherical particle. The expression is dependent upon the dielectric constant of the materials and the frequency of the light. At least, that's my take on it.
Thanks for the paper, you are right about single nanoparticles. Yet, I am concerned about their asymmetrical aggregation, specifically in case of gold nano rods. Then, would it be possible to observe different spectrum using polarized and unpolarized light, or based on the polarization; estimate the orientation?
That sounds like a topic for advanced research. I suggest you do a thorough search of the peer reviewed literature. Microscopy and spectroscopy, specifically AFM, EDS, SEM, etc., is my area of research. Not plasmonics. This is just an introductory lecture on the subject for my Introductory Nanoscience class, which is a survey course in the subject. Good luck!
Hi! thank you for making this video I would like to ask you the title of the book you just referred in this comment. Greetings from Venezuela and thank you very much for the explanation :)
Thanks! There's a link to a pdf file in my comment above that you can click on. Not sure if its a book or just a really long paper, but its helpful for plasmon theory. There's a good general intro to nanoscience textbook that I use in the course, "Nanotechnology: Understanding Small Systems" by Rogers, Pennathur and Adams. Hope that helps.
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
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.
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.
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.
Thanks everyone. Glad you enjoyed it.
can u send me litrature elated to surface plasmon resonance.
Thanks for the explanation, it was very helpful.
The best explanations on TH-cam on surface plasmons... Thanks a lot..
Thank you so much ma'am!
Thank you!
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!
I graduated awhile ago and still come back to your lecture. Keeps my brain fresh
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.
Thank so much for posting this! Clear, concise and excellent presentation.
Perfect Description. My Dissertation and defense owe it to you and your lecture. Thank you.
I'm so glad I found your channel. If you have anything on surface enhancement Raman and IR, I'll buy tickets to the first row, please
You explained so many questions to me, that I had since I started my chemistry studies, with this video. Thank you for your precise explonations!
So helpful! This is the simplest definition of surface plasmons I have found on the web.
Superb lecture..clearly explained the surface plasmons. Thanks a lot.
Thanks for sharing a very clear explanation of surface plasmons with the world!
Thank you from a freshman chemistry student struggling through a lab on this!!
Very good explanation. Thanks, Tonya!
Thank you so much for the explanation, it's very clear and helps a lot.
It is a straightforward way to explain and thank you for your nice lecture. Although I am not a physics student, it helped me so much.
Cheers.
Very educational insight about plasmonics. Thank you.
That was such a great explanation! Thank you for sharing this.
Excellent explanation of the plasmons. Thank you so much
You made it look simple! Thank you for the amazing explanation.
Thank you and very well delivered! Even a self-learner understood.
Thank you so much for the video. I'm kind of new to this field so your video helped me understand everything very easily. Thanks a lot!
One line. You're the best, professor.
Thank you for making this video and making me clear all my doubts regarding SPR 🙂
Great video, best I have seen online.
Clear and clean explanation! Thanks a lot!
Great explanation! For the first time I understand surface plasmons and how they are formed :))
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
Thank you so much for explaining this so well!! i have been struggling to understand this for some time now,and your lecture really helped
Thanks! I'm glad it helped.
I really confused about this topic on my thesis and you really good to explained about it. Thank you. You have helped many people. ☺
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 :)
Nice explanations and slides! Great work
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.
can you suggest any other resources?
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
@@soumyaa4230 You're welcome and good luck!
This video just made my life easier!!👍👌
The theory is so precisely explained. Thankyou
Excellent, made it nice and easy to understand.
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?
wow..! what a crsytal clear explanantion of a a concept so difficult to visualize..! thank you so much... respect and gratitude..!
Thank You so much for the simple and great explanation!
Bravo! very good explanation, thank you so much!
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.
I learnt a lot! Thank you so much! Great video!
That guy Bose a Bengali Physicist what an unsung hero. His work rediscovered years later. The discoverer of Boson...
This is a great job! Thanks.
Thank you very much for your explanation, it was very clear and it's been really helpful.
Great video, great explanation!
excellent explanation for surface plasmon resonance
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
Incredible lecture. I AM Synthesising Ag Nanoparticles, it helped a lot 🙃
Thank you soooo much you explain very well !
A really good video, thanks a lot.
In the graphs shown at 14:00 , does the peak absorbance always occur at a nanoparticle's SPR wavelength? or not necessarily?
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.
thank you very much ,i got much information from your this video wish you all the best
Thank you for such a beautiful explanation and apt illustration s
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.
Thank you so much. It helped me a lot.
Hey Dr Coffey! Miss attending your lectures. Hope everything is well for you.
Thank you! It is very helpful.
Best explanation ever!!
This is great, thank you!
Metals are shiny! I didn't know the surface plasmon was doing this!
WALLAH BEST ONE AMAZING GOD BLESS SHUKRAN
I am just wondering whether these resonant electrons are from valence band or conduction band.
very nice, thank you!
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.
i typed "Do mirrors reflect UV light?" into google and now im here asking what a plasmon is.haha This was very helpful and i appreciate it :}
Thank you so much.
Thanks for sharing this lecture! I've just started my PhD on plasmonic catalysis with absolutely no theoretical knowledge about it, after watching your video it all makes sense now :)
That's nice to hear. By the end of your PhD, you can come give a guest lecture to my class. Good luck.
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?)
time varying electric field component of the electromagnetic incident wave
Thank you for this explanation :)
Nice video. Thanks a lot
thank you very much. really I got basic science. please add more one by different method.
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
what are the uses of surface plasma resonance?
can you share the power point or images?
Very useful, thanks
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!
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.
Thanks for this lecture
very good
These hypothetical scenarios need an energy system principle that can replace fossil fuels energies.
Thank you mam.... Great
7:15 are those waves in the metal phonons?
Are confined metal particles the same as quantum dots??
youre a champion tysm
It's very helpful, thx..~!
Why we call it as UV-Visible absorption spectra instead of extinction spectra? Why we tell absorption peak of nanoparticles instead of extinction peak..?
What is the difference between SP and LSPR?
thx, getting my nobel prize next year
I never understand SPR through the read of many article and lecture from my professor but now I do! Great explanation! Thanks a lot!
What about the plasmons in XPS ?
@tonya coffey can you please share the slides
Thank you
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
Thank you, Dr. Coffey!
I enjoyed your lecture very much. Even if it doesn't meant to, it kinda explains the nature of refractive index. What I am puzzled with though is that how (if at all) the resonance might be affected with the polarization of incident EM wave.
According to the theory, surface plasmons can only be excited by field components that match the parallel wave vectors. If you think about a small, spherical nanoparticle suspended in a liquid, no matter how you orient the incoming wave, there will be a part of the sphere that has a parallel component to it. So the plasmon would still be excited. If you look at this link: www.photonics.ethz.ch/fileadmin/user_upload/Courses/NanoOptics/plasmonss.pdf there is a section that describes what happens for a small spherical particle. The expression is dependent upon the dielectric constant of the materials and the frequency of the light.
At least, that's my take on it.
Thanks for the paper, you are right about single nanoparticles. Yet, I am concerned about their asymmetrical aggregation, specifically in case of gold nano rods. Then, would it be possible to observe different spectrum using polarized and unpolarized light, or based on the polarization; estimate the orientation?
That sounds like a topic for advanced research. I suggest you do a thorough search of the peer reviewed literature. Microscopy and spectroscopy, specifically AFM, EDS, SEM, etc., is my area of research. Not plasmonics. This is just an introductory lecture on the subject for my Introductory Nanoscience class, which is a survey course in the subject. Good luck!
Hi! thank you for making this video I would like to ask you the title of the book you just referred in this comment. Greetings from Venezuela and thank you very much for the explanation :)
Thanks! There's a link to a pdf file in my comment above that you can click on. Not sure if its a book or just a really long paper, but its helpful for plasmon theory. There's a good general intro to nanoscience textbook that I use in the course, "Nanotechnology: Understanding Small Systems" by Rogers, Pennathur and Adams. Hope that helps.
rly cool thank you
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
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.
@@tonyacoffey5568 That makes sense, thanks!
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!
Yes of course there is always more to be understood. This is an introductory lecture for a nanoscience class that I teach.
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
Keyboard warrior
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.
@@joewebster903 She's teaching basic principles and did a superb job at it. If you don't like it, make some of your own videos.
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.