engineering

Multiple layered plasmonics

Multiple layered plasmonics is a engineering topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Multiple layered plasmonics rather than just read about it. In short: Multiple layered plasmonics use electronically responsive media to change and manipulate the plasmonic properties of plasmons. The properties typically being manipulated can include the directed scattering of light and light absorption.

Key takeaways

Multiple layered plasmonics belongs to engineering; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Multiple layered plasmonics to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Multiple layered plasmonics from memory before moving on to harder problems.

Reference excerpt

Multiple layered plasmonics use electronically responsive media to change and manipulate the plasmonic properties of plasmons. The properties typically being manipulated can include the directed scattering of light and light absorption. The use of these to use “changeable” plasmonics is currently undergoing development in the academic community by allowing them to have multiple sets of functions that are dependent on how they are being manipulated or excited. Under these new manipulations, such as multiple layers that respond to different resonant frequencies, their new functions were designed to accomplish multiple objectives in a single application.

Overview This article provides an overview of current developing medical usage of multiple layered plasmonics, more specifically those developed by the Halas Group at Rice University In addition to the bio-medical applications purposed, several other uses will be briefly described below.

Bio-medical applications Gold shelled nanoparticles, which are spherical nanoparticles with silica cores and gold shells, are used in cancer therapy and bio imaging enhancement. Theranostic probes – capable of detection and treatment of cancer in a single treatment - are nanoparticles that have binding sites on their shell that allow them to attach to a desired location (typically cancerous cells) then can be imaged through dual modality imagery (an imaging strategy that uses x-rays and radionuclide imaging) and through near-infrared fluorescence. The reason gold nanoparticles are used is due to their vivid optical properties which are controlled by their size, geometry, and their surface plasmons. Gold nanoparticles (such as AuNPs) have the benefit of being biocompatible and the flexibility to have multiple different molecules and fundamental materials, attached to their shell (almost anything that can normally be attached to gold can be attached to the gold nano-shell, helping in identifying and treating cancer). The treatment of cancer is possible only because of the scattering and absorption that occurs for plasmonics. Under scattering, the gold plated nanoparticles become visible to imaging processes that are tuned to the correct wavelength which is dependent upon the size and geometry of the particles. Under absorption, photothermal ablation occurs, which heats the nanoparticles and their immediate surroundings to temperatures capable of killing the surrounding cells. Additionally, these nanoparticles can be made to release antisense DNA oligonucleotides when under photo-activation. These oligonucleotides are used in conjunction with the photo-thermal ablation treatments to perform gene-therapy. This is accomplished because nanoparticle complexes are delivered inside of cells then undergo light induced release of DNA from their surface. This will allow for the internal manipulation of a cell and provide a means for monitoring a group cells return to equilibrium. Another example of multiple layered plasmonics involves placing drugs inside of the nanoparticle and using it as a vehicle to deliver toxic drugs to cancerous sites only. This is accomplished by coating the outside of a nanoparticle with iron oxide (allowing for easy tracking with an MRI machine) then once the area of the tumor is coated with the drug filled nanoparticles, the nanoparticles can be activated using resonant light waves to release the drug.

Other applications

Active plasmonics Multiple layered plasmonics can be coated in nanoparticles to modify or drive a reaction near a metallic surface when properly excited. Additionally, the scattering of light from these plasmonics can be controlled and even directed based on the surface particles, geometry, and size.

Energy applications Multiple layered plasmonics can be used in harvesting solar radiation for energy applications. This is accomplished by redirecting incident light into the waveguide and evanescent surface modes of thin film photovoltaic devices. Using multiple layered plasmons to purify water is also being investigated. For more information on the research behind energy applications, and the collaborations behind this research, please visit the Halas group website listed below in the external links.

References

External links halas.rice.edu

Worked examples

Example 1 — a first encounter with Multiple layered plasmonics

Start with the simplest possible case. Write down what Multiple layered plasmonics claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In engineering, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Multiple layered plasmonics before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Multiple layered plasmonics ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Multiple layered plasmonics

In research: Multiple layered plasmonics appears in engineering research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Multiple layered plasmonics in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Multiple layered plasmonics is common in secondary-school and first-year university syllabi. It links to neighbouring topics Metamaterials, Plasmonics, so understanding it makes those chapters shorter.
In everyday life: Look for Multiple layered plasmonics outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Multiple layered plasmonics in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Multiple layered plasmonics means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Multiple layered plasmonics out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Multiple layered plasmonics in simple terms?

Why does Multiple layered plasmonics matter?

Because it connects several engineering ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Multiple layered plasmonics?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Multiple layered plasmonics.