Subscribe to our free daily newsletters
. 24/7 Space News .




Subscribe to our free daily newsletters



CARBON WORLDS
Ultrathin and flat graphene metalenses gain morace properties
by Staff Writers
Seoul, South Korea (SPX) Nov 30, 2017


Metalenses are ultrathin (around 25 micrometers in thickness) and also very flat compared with conventional ones.

On the quest for miniaturization, scientists at the Center for Integrated Nanostructure Physics, within the Institute for Basic Science (IBS, South Korea), in collaboration with researchers from the University of Birmingham and the Korea Advanced Institute of Science and Technology (KAIST), develop credit card-thick, flat lenses with tunable features. These optical devices, made of graphene and a punctured gold surface, could become optical components for advanced applications, such as amplitude tunable lenses, lasers (i.e. vortex phase plates), and dynamic holography.

Metasurfaces are new 2D materials that can effectively control the electric and magnetic components of light (and other electromagnetic waves) and bend them to bespoken directions. Controlling the beam's direction can bring out interesting phenomena; the most incredible being the "invisibility cloak effect", where light waves bypass an object recreating the image beyond the object, as flowing water in a river would bypass a stone.

Published in Advanced Optical Materials, the study presents the properties of a metasurface which works as a convex lens. Specifically, it is made of a gold sheet pierced with micrometer-sized U-shaped holes and covered with graphene.

As the shape of common convex lenses allows light to be concentrated on a spot (or focus), think about a magnifying glass which can concentrate a light beam and even start a fire, so the particular pattern of the tiny apertures of the metalenses works by focusing the incoming beam.

In addition, these microholes can also change light polarization. While natural light is generally unpolarized before being reflected, the team used circularly polarized waves, that is a light beam where the direction of the electric field is corkscrew spiraling.

This metalens can convert the left-circular polarization wave (going counterclockwise if seen straight in front) to right-circular polarization (clockwise). The researchers managed to obtain a conversion rate of 35%. Converting circular polarization could be useful in a number of fields, for example biosensing and telecommunications.

In order to control even more properties, the scientists took advantage of graphene's unique electronic features and used them to tune the output beam's intensity or amplitude. Here graphene plays the role of the exposure of a camera. In the case of the camera, a mechanical control allows a certain shutter's opening time and size to determine the amount of light entering the instrument.

These metalenses instead, regulate the exposure via an electric tension applied to the graphene sheet, without the need for bulky components. When voltage is applied to the graphene layer, the output beam becomes weaker. "Using metalenses, you can make microscopes, cameras, and tools used in very sensitive optical measurements, much more compact," clarifies Teun-Teun Kim, the first author of the study.

The metalenses were designed for a type of electromagnetic wave, which falls in-between infrared radiation and microwave radiation, called terahertz radiation. This type of radiation can pass through some materials (like fabrics and plastics), but at a shorter depth than microwave radiation, for this reason it is employed for surveillance and security screening.

"While conventional optical lenses have a thickness of several centimeters to several millimeters, this metalens is just a few tens of micrometers thick. The intensity of the focused light can be effectively controlled and it could find useful applications in ultra-small optical instruments," highlights the scientists.Teun-Teun Kim, the first author of the study.

Research paper

CARBON WORLDS
New graphene filter turns whiskey clear
Washington (UPI) Nov 14, 2017
Scientists have created a new graphene-oxide membrane capable of turning whiskey clear. Previous graphene-oxide filters proved impermeable to all but water, limiting their potential. But researchers at the University of Manchester found they could let other solvents through by making the graphene-oxide membrane extremely thin. During the membrane's assembly, pinholes become inter ... read more

Related Links
Institute for Basic Science
Carbon Worlds - where graphite, diamond, amorphous, fullerenes meet


Thanks for being here;
We need your help. The SpaceDaily news network continues to grow but revenues have never been harder to maintain.

With the rise of Ad Blockers, and Facebook - our traditional revenue sources via quality network advertising continues to decline. And unlike so many other news sites, we don't have a paywall - with those annoying usernames and passwords.

Our news coverage takes time and effort to publish 365 days a year.

If you find our news sites informative and useful then please consider becoming a regular supporter or for now make a one off contribution.

SpaceDaily Contributor
$5 Billed Once


credit card or paypal
SpaceDaily Monthly Supporter
$5 Billed Monthly


paypal only

Comment using your Disqus, Facebook, Google or Twitter login.

Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle

CARBON WORLDS
Does the Outer Space Treaty at 50 need a rethink

NASA to send critical science, instruments to Space Station

Can a magnetic sail slow down an interstellar probe

SSL Selected to Conduct Power and Propulsion Study for NASA's Deep Space Gateway Concept

CARBON WORLDS
Flat-Earther's self-launch plan hits a snag

SSTL ships CARBONITE-2 and Telesat's LEO-1 for PSLV launch

Aerojet Rocketdyne supports ULA Delta II launch of JPSS-1

Old Rivals India, China Nurture New Rivalry in Satellite Launch Business

CARBON WORLDS
Gadgets for Mars

Ice shapes the landslide landscape on Mars

Winds Blow Dust off the Solar Panels Improving Energy Levels

Previous evidence of water on Mars now identified as grainflows

CARBON WORLDS
Nation 'leads world' in remote sensing technology

China plans for nuclear-powered interplanetary capacity by 2040

China plans first sea based launch by 2018

China's reusable spacecraft to be launched in 2020

CARBON WORLDS
Need to double number of operational satellites: ISRO chief

Space Launch plans UK industry tour

Astronaut meets volcano

European Space Week starts in Estonia

CARBON WORLDS
New way to write magnetic info could pave the way for hardware neural networks

Device could reduce the carbon footprint of ethylene production

Researchers inadvertently boost surface area of nickel nanoparticles for catalysis

X-rays reveal the biting truth about parrotfish teeth

CARBON WORLDS
First known interstellar visitor is an 'oddball'

Lava or Not, Exoplanet 55 Cancri e Likely to have Atmosphere

Images of strange solar system visitor peel away some of the mystery

Familiar-Looking Messenger from Another Solar System

CARBON WORLDS
Pluto's hydrocarbon haze keeps dwarf planet colder than expected

Jupiter's Stunning Southern Hemisphere

Watching Jupiter's multiple pulsating X-ray Aurora

Help Nickname New Horizons' Next Flyby Target




Memory Foam Mattress Review
Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News






The content herein, unless otherwise known to be public domain, are Copyright 1995-2017 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. All articles labeled "by Staff Writers" include reports supplied to Space Media Network by industry news wires, PR agencies, corporate press officers and the like. Such articles are individually curated and edited by Space Media Network staff on the basis of the report's information value to our industry and professional readership. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement