Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Two crystals are better than one

22.07.2015

Engineered structures that can alter the speed of light could benefit optical communication systems

A method for designing materials capable of slowing the propagation of light over a broad range of wavelengths has been developed by researchers at the A*STAR Institute of High Performance Computing [1].


Combining photonic crystals can slow the propagation of light for applications in optical communications. © 2015 A*STAR Institute of High Performance Computing

The speed of light in a vacuum is always constant — a fundamental concept made famous by Albert Einstein. But light propagates more slowly when it enters a different medium, such as glass.

The degree to which the speed is reduced is given by a material’s dielectric constant — a higher dielectric constant indicates slower propagation. Rather than rely on a limited source of natural substances, scientists have started to design optical materials with a broader range of beneficial properties including ‘slow’ light.

One approach is to combine two materials with different dielectric constants into a periodic structure. This can result in properties that dramatically differ from those of the constituent materials, particular when the length scale of the periodicity is similar to the wavelength of light.

“These so-called photonic crystals, when appropriately designed and in ideal conditions, can almost stop the propagation of light altogether,” says A*STAR scientist Gandhi Alagappan.

The requirement that the periodicity of the structure be similar to the wavelength of interest, however, is a limitation for practical applications. It means that most of these materials only work with light of a single color. Alagappan and his co-worker Jason Ching Png have now developed a scheme for designing photonic crystals that operate over a broader range of wavelengths.

Alagappan and Png considered a structure in which two different materials are layered on top of each other. To obtain two different periodicities, however, a third material with a dielectric constant midway between the two other materials would typically be needed.

This makes physically creating the structure difficult. The researchers instead focused on developing a mathematical technique to combine two materials in such a way that the dielectric profile in the stacking direction is almost the same as in the more complicated three-material structure (see image).

Alagappan and Png simulated the optical properties of their combined photonic crystal. They identified a broad range of wavelengths known as the strong coupling region that has a high density of slow modes.

“We have invented a linear optical multi-scale architecture that facilitates the creation of broadband slow light,” says Alagappan. “The proposed structure could potentially revolutionize current optical buffering technologies.”

The A*STAR-affiliated researchers contributing to this research are from the Institute of High Performance Computing. More information about the group’s research can be found at the Photonics and Plasmonics Group webpage.

Reference

[1] Alagappan, G. & Png, C. E. Broadband slow light in one-dimensional logically combined photonic crystals. Nanoscale 7, 1333–1338 (2015).


Associated links
A*STAR Research article

A*STAR Research | ResearchSEA
Further information:
http://www.researchsea.com

More articles from Information Technology:

nachricht Powerful IT security for the car of the future – research alliance develops new approaches
25.05.2018 | Universität Ulm

nachricht Supercomputing the emergence of material behavior
18.05.2018 | University of Texas at Austin, Texas Advanced Computing Center

All articles from Information Technology >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Powerful IT security for the car of the future – research alliance develops new approaches

The more electronics steer, accelerate and brake cars, the more important it is to protect them against cyber-attacks. That is why 15 partners from industry and academia will work together over the next three years on new approaches to IT security in self-driving cars. The joint project goes by the name Security For Connected, Autonomous Cars (SecForCARs) and has funding of €7.2 million from the German Federal Ministry of Education and Research. Infineon is leading the project.

Vehicles already offer diverse communication interfaces and more and more automated functions, such as distance and lane-keeping assist systems. At the same...

Im Focus: Molecular switch will facilitate the development of pioneering electro-optical devices

A research team led by physicists at the Technical University of Munich (TUM) has developed molecular nanoswitches that can be toggled between two structurally different states using an applied voltage. They can serve as the basis for a pioneering class of devices that could replace silicon-based components with organic molecules.

The development of new electronic technologies drives the incessant reduction of functional component sizes. In the context of an international collaborative...

Im Focus: LZH showcases laser material processing of tomorrow at the LASYS 2018

At the LASYS 2018, from June 5th to 7th, the Laser Zentrum Hannover e.V. (LZH) will be showcasing processes for the laser material processing of tomorrow in hall 4 at stand 4E75. With blown bomb shells the LZH will present first results of a research project on civil security.

At this year's LASYS, the LZH will exhibit light-based processes such as cutting, welding, ablation and structuring as well as additive manufacturing for...

Im Focus: Self-illuminating pixels for a new display generation

There are videos on the internet that can make one marvel at technology. For example, a smartphone is casually bent around the arm or a thin-film display is rolled in all directions and with almost every diameter. From the user's point of view, this looks fantastic. From a professional point of view, however, the question arises: Is that already possible?

At Display Week 2018, scientists from the Fraunhofer Institute for Applied Polymer Research IAP will be demonstrating today’s technological possibilities and...

Im Focus: Explanation for puzzling quantum oscillations has been found

So-called quantum many-body scars allow quantum systems to stay out of equilibrium much longer, explaining experiment | Study published in Nature Physics

Recently, researchers from Harvard and MIT succeeded in trapping a record 53 atoms and individually controlling their quantum state, realizing what is called a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

In focus: Climate adapted plants

25.05.2018 | Event News

Save the date: Forum European Neuroscience – 07-11 July 2018 in Berlin, Germany

02.05.2018 | Event News

Invitation to the upcoming "Current Topics in Bioinformatics: Big Data in Genomics and Medicine"

13.04.2018 | Event News

 
Latest News

In focus: Climate adapted plants

25.05.2018 | Event News

Flow probes from the 3D printer

25.05.2018 | Machine Engineering

Less is more? Gene switch for healthy aging found

25.05.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>