Metalens achieves nearunity numerical aperture

first_imgIllustration of the new optical lens with a near-unity numerical aperture. Credit: Paniagua-Domínguez et al. ©2018 American Chemical Society This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only. The researchers, led by Arseniy Kuznetsov and Ramón Paniagua-Domínguez, at A*STAR (Agency for Science, Technology, and Research) and Nanyang Technological University, both in Singapore, have published a paper on the lens with near-unity numerical aperture in a recent issue of Nano Letters.Previously, the highest numerical aperture for a free-space lens was 0.95, which corresponds to a maximum collection angle of around 72°. Due to the way these lenses are made, they are also large and expensive, and so cannot be easily scaled down to work with very small systems.With its numerical aperture of 0.99, the new lens has both a higher resolution and a larger collection angle of 82°. The new lens is made of a metasurface rather than traditional lens materials. The metasurface consists of a pattern of subwavelength-scale structures and has an overall thickness of less than one wavelength of light, resulting in a small size that greatly expands its potential applications.”High-numerical aperture lenses/microscope objectives are major optical components that are widely used in microscopy, optical detection systems, optical lithography, quantum optics, etc.,” Kuznetsov told Phys.org. “Having a high numerical aperture is of primary importance in achieving a high resolution and high detection level of optical signals. Currently existing high-numerical-aperture lenses/microscope objectives are bulky and expensive. In this work, we showed that, using a new concept of metasurfaces based on dielectric nanoantennas, it is possible to design and realize flat optical components that can achieve a numerical aperture higher than all existing optical objectives, using just a device just a few hundred nanometers thick.”To demonstrate the advantages of the new lens, the researchers used it to image nitrogen-vacancy centers in diamond nanocrystals, which are several tens of nanometers in size. The images scanned by the new metalens revealed smaller spots compared to images scanned using commercial lenses with smaller numerical apertures, demonstrating the new lens’ higher resolution.The researchers expect that, in the future, the new lens may also be used to make improvements to photolithography, which is used to produce computer chips and other high-resolution devices. In addition, the new lens’ wide-angle collection is expected to increase the efficiency of single-photon emission processes, which are used in quantum optics systems.”We believe that this new concept will find broad applications in areas where detection of weak optical signals is important,” Kuznetsov said. “One example is in quantum optics, which deals with systems containing only single atoms or quantum emitters emitting light at the single-photon level. Such flat lenses not only allow for the detection of weak optical signals, but also can operate at extreme conditions of low temperatures and in vacuum, which is typical for quantum optics experiments.”Another important application direction could be in wearable and mobile photonic devices, where dense integration of high-efficiency optical components is required. For example, the lenses could find applications in mobile phone cameras and augmented reality glasses.” Nanostructured thin-films that can bend light by large angles could be a replacement for bulky glass optical components Explore further More information: Ramón Paniagua-Domínguez et al. “A Metalens with a Near-Unity Numerical Aperture.” Nano Letters 18, 2124–2132 (2018). DOI: 10.1021/acs.nanolett.8b00368center_img Researchers have designed an optical lens with the highest free-space numerical aperture to date, achieving a value of just under 1. As the numerical aperture indicates the highest possible resolution that a lens can attain, the new lens can focus light with unprecedented ability, as well as collect light from wide angles. These abilities should make the lens particularly useful for low-light applications, such as single-photon emission, which is often used in quantum optics systems. Journal information: Nano Letters Citation: Metalens achieves near-unity numerical aperture (2018, March 26) retrieved 18 August 2019 from https://phys.org/news/2018-03-metalens-near-unity-numerical-aperture.html © 2018 Phys.orglast_img read more

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first_imgShareTweet POLITICIANS have condemned those who have forced a children’s play park in Derry to shut after it was vandalised yet again.The vandalism is the latest in a long line of attacks at Ballymagowam in the Creggan area.Rubber safety matting was damaged and coping stones smashed with a hammer in the latest incident which happened on Thursday night. Local Sinn Fein councillor Kevin Campbell has condemned those who have children of a safe place to play.“Apex have now closed the play park on the grounds of health and safety until they get these problems rectified.“I am appealing to parents to have a conversation with your children around vandalism of the park.”He added that he will be working with Apex to have the park reopened as soon as possible.” MINDLESS VANDALS FORCE DERRY PLAY PARK TO BE CLOSED DOWN was last modified: October 14th, 2016 by John2John2 Tags: apexballymagowanCOUNCILLOR KEVIN CAMPBELLCRegganMINDLESS VANDALS FORCE DERRY PLAY PARK TO CLOSED DOWNSinn Feinlast_img read more

CHIEF INSPECTOR MARK MCCLARENCEdrumahoeLETTERSHAND

first_img CHIEF INSPECTOR MARK MCCLARENCEdrumahoeLETTERSHANDONEY AVENUEPOLICE URGE PUBLIC VIGILANCE AFTER NOTHING FOUND IN DERRY SEARCHES POLICE in Foyle investigating a report of suspicious activity have carried out a number of searches in but nothing has been found.The searches were carried out in the Lettershandoney Avenue area of DrumahoeChief Inspector Mark McClarence said:  “I would like to thank local residents for their patience during the policing operation today. ShareTweetcenter_img “The safety of the public is our first priority and searches were carried out following a report received by police in order to keep people safe.“Whilst nothing suspicious was found, I would continue to ask residents to remain vigilant and to report anything untoward to police on 101.”POLICE URGE PUBLIC VIGILANCE AFTER NOTHING FOUND IN DERRY SEARCHES was last modified: January 22nd, 2017 by John2John2 Tags:last_img read more