Mapping gigahertz vibrations in a plasmonic–phononic crystal
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| Anzahl der Teile | 63 | |
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| Lizenz | CC-Namensnennung 3.0 Unported: Sie dürfen das Werk bzw. den Inhalt zu jedem legalen Zweck nutzen, verändern und in unveränderter oder veränderter Form vervielfältigen, verbreiten und öffentlich zugänglich machen, sofern Sie den Namen des Autors/Rechteinhabers in der von ihm festgelegten Weise nennen. | |
| Identifikatoren | 10.5446/39033 (DOI) | |
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00:00
NiederspannungsnetzElementarteilchenphysikGleitlagerVideotechnikKristallwachstumAchtzig-Zentimeter-KanoneÖffentliches VerkehrsmittelLichtPlasmonPatrone <Munition>KristallstrukturMie, GustavAtmosphärische StörungHaspel <Textiltechnik>DrehmasseFACTS-AnlageKontraktionBuntheitModellbauerTeilchenrapiditätElektronische MedienGleitlagerComputeranimationBesprechung/Interview
00:54
FACTS-AnlageKristallwachstumArrayRucksackPfadfinder <Flugzeug>KristallstrukturBesprechung/Interview
01:01
ElektronenmikroskopPfadfinder <Flugzeug>KristallstrukturSpeckle-Interferometrie
01:15
IntensitätsverteilungFlugsimulatorÖffentliches VerkehrsmittelLichtBesprechung/Interview
01:24
KristallwachstumBesprechung/Interview
01:32
PlasmonHammerKristallwachstumPhysikalisches ExperimentBesprechung/Interview
01:46
SensorLaserFamilie <Elementarteilchenphysik>Gauß-BündelMikroskopobjektivPhotographische PlatteIntensitätsverteilungInfrarotlaserLichtLaserComputeranimation
02:11
ResonanzenergieQuantenfluktuationKristallstrukturIntensitätsverteilungMonatComputeranimation
02:40
Angeregter ZustandNiederfrequenzMassenresonanzHammerStörstelleComputeranimation
03:08
ErdefunkstelleÖffentliches VerkehrsmittelKalenderjahrComputeranimation
03:25
StörstelleElektrisches SignalResonanzenergieKalenderjahrComputeranimation
03:41
KristallwachstumAkustooptischer ModulatorMessungMotorSchiffsklassifikationNiederfrequenzTelefonVorlesung/KonferenzBesprechung/Interview
04:21
SchmalfilmBesprechung/Interview
Transkript: Englisch(automatisch erzeugt)
00:03
Mental structures like this golden crown or goblet here can trap light. Since the goblet is very smooth, it's not hard to imagine the light going round and round inside forming electromagnetic modes. The objective of our research is to modulate light in vibrating goblets.
00:24
If the goblet is very small with sub-micron radius then we call the electromagnetic modes plasmons or more specifically Mie-like plasmons after the German scientist Gustav Mie. Violet? More goblets!
00:43
Let's arrange them like this. Our sample is in fact a close packed array of golden goblets forming a plasmonic crystal.
01:02
A section of the sample is shown here together with an electron microscope image. The truncated nanovoids intersect a bit giving an interconnected structure marked by triangular pillars. Electromagnetic simulations like this one for blue light confirm that the light in Mie modes is concentrated inside the nanovoids.
01:24
To produce vibrations what we effectively do is take a hammer and strike the plasmonic crystal. These vibrations show that it's not just a plasmonic crystal, it's also a phononic crystal. Actually instead of a hammer we use ultra-short light pulses.
01:46
In the experiment red laser light pulses create tiny vibrations by heating a small sub-micron spot. Blue light pulses detect the vibrations through intensity changes at the same point.
02:00
These are very high-pitched vibrations around 1 GHz. We scan the sample position and change the timing of the laser pulses to make movies. Here is an example for a 6 micron square area. It is slowed down a thousand million times. The intensity fluctuations are caused by the structure flexing.
02:25
We process the data to extract the vibrational frequencies one by one like this example at around 0.7 GHz where we see a strong mechanical resonance. The hexagon encloses a region with seven nanovoids.
02:40
By averaging the data we can form a good picture of where the vibrations are most efficiently generated and detected. Here you can see them very strongly at the centre of the nanovoids at three different vibrational resonance frequencies. We can also watch the variation in time at these frequencies as movies. To understand these data, let's look at a numerical simulation
03:04
corresponding to a hammer blow to the centre of a nanovoid. This produces acoustic modes, analogous to the electromagnetic modes I've already mentioned. This is a side view of the sample motion at around 1 GHz. You can see the central nanovoid periodically opening and closing.
03:25
It's just like a golden goblet opening and closing. This breathing motion changes the nanovoid plasmonic resonances. We believe that the plasmonic response is enhancing the observed signals we detect from the void centre.
03:41
So we can map vibrations in a plasmonic phononic crystal. If you think that's a mouthful, you can say plasphonic crystal. Engineering both the plasmonic and phononic properties of our plasmonic crystal to enhance the optomechanical interactions could open up the possibility for novel devices
04:01
such as high-frequency acousto-optic modulators. I shall conclude by drinking your health in a plasmonic void. Mead wallet! A measure of mead! Yes!