Plasmonic Device Achieves 90-GHz Switching

DURHAM, N.C., July 27, 2015 — Able to flip on and off 90 billion times a second, a new plasmonic light emitter could form the basis of optical computing.

“This is something that the scientific community has wanted to do for a long time,” said Duke University professor Maiken Mikkelsen, whose team developed the device. “We can now start to think about making fast-switching devices based on this research, so there’s a lot of excitement about this demonstration.”

The device consists of a 75-nm silver cube and a thin sheet of gold, with 6-nm quantum dots (QDs) sandwiched in between. Laser illumination generates plasmons on the cube’s surface, which creates an intense electromagnetic field that triggers the QDs, producing directional, efficient emission of photons that can be turned on and off at a rate of more than 90 GHz.

Superfast fluorescence system


Transmission electron microscope view of a superfast fluorescence system. The silver cube is 75 nm wide. The quantum dots (red) are sandwiched between the silver cube and a thin gold foil. Courtesy of Maiken Mikkelsen/Duke University.


“There is great interest in replacing lasers with LEDs for short-distance optical communication, but these ideas have always been limited by the slow emission rate of fluorescent materials, lack of efficiency and inability to direct the photons,” said postdoctoral researcher Gleb Akselrod. “Now we have made an important step towards solving these problems.”

“The eventual goal is to integrate our technology into a device that can be excited either optically or electrically,” said Thang Hoang, also a postdoctoral researcher in Mikkelsen’s laboratory. “That’s something that I think everyone, including funding agencies, is pushing pretty hard for.”

The group is now working to use the plasmonic structure to create a single-photon source — a necessity for extremely secure quantum communications — by sandwiching a single QD in the gap between the silver nanocube and gold foil. They are also trying to precisely place and orient the QDs to create the fastest fluorescence rates possible.

Aside from its potential technological impacts, the research demonstrates that well-known materials need not be limited by their intrinsic properties, the researchers said.

“By tailoring the environment around a material, like we’ve done here with semiconductors, we can create new designer materials with almost any optical properties we desire,” Mikkelsen said. “And that’s an emerging area that’s fascinating to think about.”

Funding came from the U.S. Air Force Office of Scientific Research, an Oak Ridge Associated University’s Ralph E. Powe Junior Faculty Enhancement Award, the Lord Foundation of North Carolina and the Intelligence Community Postdoctoral Research Fellowship Program.

The research was published in Nature Communications (doi: 10.1038/ncomms8788).

For more information, visit www.duke.edu.

 

Source: http://www.photonics.com/Article.aspx?PID=6&VID=124&IID=830&AID=57603

 




Plasmon Wakes Created, Controlled in Metamaterial

CAMBRIDGE, Mass., July 7, 2015 — Surface plasmons can exhibit wakes likes any other wave, and those wakes can be controlled through nanoscale features on a metallic surface and through properties of the light shining on it.

The creation and control of surface plasmon wakes could lead to new types of plasmonic couplers and lenses that could create 2D holograms or focus light at the nanoscale, according to researchers at Harvard University.

“The ability to control light is a powerful one,” said professor Federico Capasso. “Our understanding of optics on the macroscale has led to holograms, Google Glass and LEDs, just to name a few technologies. Nano-optics is a major part of the future of nanotechnology, and this research furthers our ability to control and harness the power of light on the nanoscale.”

Plasmon wake


An artist’s rendering of a running wave of polarization that excites the surface plasmon wakes. Courtesy of Daniel Wintz, Patrice Genevet and Antonio Ambrosio.


Capasso’s team generated running waves of polarization that propagated faster than the phase velocity of the plasmons along a 1D metamaterial. This created wakes analogous to those responsible for Cherenkov radiation.

The metamaterial, a nanostructure of rotated slits etched into a gold film, changes the phase of the surface plasmons generated at each slit relative to each other, increasing the velocity of the running wave. The nanostructure also acts like a boat’s rudder, allowing the wakes to be steered by controlling the speed of the running wave.

The angle of incidence and photon spin angular momentum of the light shining onto the metamaterial determines the speed of the running wave of polarization and thus provides an additional measure of control. The team also discovered that using polarized light can even reverse the direction of the wake relative to the running wave — like a wake traveling in the opposite direction of a boat.

“Being able to control and manipulate light at scales much smaller than the wavelength of the light is very difficult,” said graduate student Daniel Wintz. “It’s important that we not only observed these wakes but found multiple ways to control and steer them.”

The observation itself was challenging, as “surface plasmons are not visible to the eye or cameras,” said Antonio Ambrosio, a postdoctoral fellow at Harvard and researcher at the Italian Research Council. “In order to view the wakes, we used an experimental technique that forces plasmons from the surface, collects them via fiber optics and records the image.”

This work could represent a new testbed for wake physics across a variety of disciplines, the researchers said.

“This research addresses a particularly elegant and innovative problem in physics which connects different physical phenomena, from water wakes to sonic booms, and Cherenkov radiation,” said Patrice Genevet, a former Harvard postdoctoral scholar currently affiliated with the Singapore Institute of Manufacturing Technology.

Funding came from the National Science Foundation and U.S. Air Force Office of Scientific Research.

The research was published in Nature Nanotechnology (doi: 10.1038/nnano.2015.137).

For more information, visit seas.harvard.edu.

 

Source: http://www.photonics.com/Article.aspx?PID=5&VID=125&IID=838&AID=57563




SPIE announces 2015 award winners

Gold Medal of the Society goes to University of Pennsylvania professor Nader Engheta

06 March 2015

BELLINGHAM, Washington, USA — Winners of prestigious annual awardshave been announced by the Awards Committee of SPIE, the international society for optics and photonics. The awards recognize outstanding individual and team technical accomplishments and meritorious service to the Society.

Award winners for 2015 are:

Gold Medal of the Society: Nader Engheta, University of Pennsylvania, for his transformative and groundbreaking contributions to optical engineering of metamaterials and nanoscale plasmonics, metamaterial-based optical nano circuits, and biologically-inspired optical imaging. The Gold Medal is the highest honor bestowed by SPIE.

 

Nader EnghetaNader Engheta,
2015 Gold Medal
of the Society
recipient

 

Britton Chance Biomedical Optics Award: Lihong Wang, Washington University in St. Louis, for his pioneering technical contributions and visionary leadership in the development and application of photo-acoustic tomography, photoacoustic microscopy and photon transport modeling.

A.E. Conrady Award: Richard C. Juergens, Raytheon Missile Systems, recognizing him as a leading authority in optical system design, optical component fabrication and testing, and training and mentoring of optical engineers, and instrumental in developing optimization techniques and tolerancing methods for optical design.

Dennis Gabor Award: Kazuyoshi Itoh, Osaka University, for his eminent contribution to the development of incoherent holography and nonlinear optical microscopy through your pioneering work on coherence-based multispectral and 3D imaging, and nonlinear optical imaging and manipulations of biological and inorganic industrial materials.

George W. Goddard Award: Grady H. Tuell, Georgia Tech Research Institute, recognizing his foundational research and development in bathymetric lidar and data fusion; and his efforts to further advance airborne LIDAR remote sensing in other ways including real-time calculation of total propagated positioning error.

G.G. Stokes Award: Aristide Dogariu, CREOL, University of Central Florida, for his development of new theoretical concepts and innovative methods and techniques for understanding and measuring polarization properties of light-matter interaction.

Chandra S. Vikram Award in Optical Metrology: Guillermo H. Kaufmann, Instituto de Física Rosario (CONICET-UNR) for his contributions to speckle metrology and its applications in material science, experimental mechanics and nondestructive testing, and also for the development of novel fringe analysis methods.

Frits Zernike Award in Microlithography: Ralph R. Dammel, AZ Electronics Materials, for his significant contributions to the development of photoresist, anti-reflective coating, and directed self-assembly materials for semiconductor microlithography.

SPIE Early Career Achievement Award — Academic: Miriam Serena Vitiello, recognizing her outstanding results in research on semiconductor laser sources and electronic high frequency nanodetectors which have opened new frontiers in the Terahertz photonics and optoelectronics fields.

SPIE Early Career Achievement Award — Industry: Alan Lee, LongWave Photonics LLC, recognizing his pioneering research on stand-off distance real-time THz imaging. The locking-in differential imaging proposed in his work formed the basic working principle of several commercial THz imagers/cameras.

SPIE Educator Award: Virendra Mahajan, recognizing his sharing of knowledge in the area of optical imaging, aberrations, and wavefront analysis through his voluntary teaching of students and professionals and the writing of five excellent books.

SPIE Technology Achievement Award: Keith B. Doyle, MIT Lincoln Laboratory, for his outstanding contributions to integrated analysis of optical systems, incorporating in this analysis elements of optical, thermal, and structural engineering.

For future awards, members of the photonics community may nominate colleagues to recognize their outstanding achievements. Nominations may be made through October 1 of any given year and are considered active for three years from the submission date. Instructions and nomination forms are at www.spie.org/x1164.xml.

SPIE is the international society for optics and photonics, a not-for-profit organization founded in 1955 to advance light-based technologies. The Society serves nearly 256,000 constituents from approximately 155 countries, offering conferences, continuing education, books, journals, and a digital library in support of interdisciplinary information exchange, professional networking, and patent precedent. SPIE provided more than $3.4 million in support of education and outreach programs in 2014.

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Source:http://spie.org/x112992.xml