Ultra-fast Data Processing At Nanoscale

Advancement in nanoelectronics, which is the use of nanotechnology in electronic components, has been fueled by the ever-increasing need to shrink the size of electronic devices like nanocomputers in a bid to produce smaller, faster and smarter gadgets such as computers, memory storage devices, displays and medical diagnostic tools.

While most advanced electronic devices are powered by photonics – which involves the use of photons to transmit informationphotonic elements are usually large in size and this greatly limits their use in many advanced nanoelectronics systems. Plasmons, which are waves of electrons that move along the surface of a metal after it is struck by photons, holds great promise for disruptive technologies in nanoelectronics. They are comparable to photons in terms of speed (they also travel with the speed of light), and they are much smaller. This unique property of plasmons makes them ideal for integration with nanoelectronics. However, earlier attempts to harness plasmons as information carriers had little success.

Addressing this technological gap, a research team from the National University of Singapore (NUS) has recently invented a novel “converter” that can harness the speed and small size of plasmons for high frequency data processing and transmission in nanoelectronics.

This innovative transducer can directly convert electrical signals into plasmonic signals, and vice versa, in a single step. By bridging plasmonics and nanoscale electronics, we can potentially make chips run faster and reduce power losses. Our plasmonic-electronic transducer is about 10,000 times smaller than optical elements. We believe it can be readily integrated into existing technologies and can potentially be used in a wide range of applications in the future,” explained Associate Professor Christian Nijhuis from the Department of Chemistry at the NUS Faculty of Science, who is the leader of the research team behind this breakthrough.

This novel discovery was first reported in the journal Nature Photonics.

Source: http://news.nus.edu.sg/

Compact, Ultra Sensitive BioSensor Gives Infos From A Blood Drop

Imagine a hand-held environmental sensor that can instantly test water for lead, E. coli, and pesticides all at the same time, or a biosensor that can perform a complete blood workup from just a single drop. That’s the promise of nanoscale plasmonic interferometry, a technique that combines nanotechnology with plasmonics—the interaction between electrons in a metal and light.

Now researchers from Brown University’s School of Engineering have made an important fundamental advance that could make such devices more practical. The research team has developed a technique that eliminates the need for highly specialized external light sources that deliver coherent light, which the technique normally requires. The advance could enable more versatile and more compact devices.

  • FluorescencePlasmonicInterferometryPlasmonic interferometers that have light emitters within them could make for better, more compact biosensors.

It has always been assumed that coherent light was necessary for plasmonic interferometry,” said Domenico Pacifici, a professor of engineering who oversaw the work with his postdoctoral researcher Dongfang Li, and graduate student Jing Feng. “But we were able to disprove that assumption.”

The research is described in Nature Scientific Reports.

Source: https://news.brown.edu/

How to “Grow” Billions Of Light Dots Directly On Chips

Researchers from the University of California, Santa Barbara (UCSB), in collaboration with the DARPA, succeeded to grow lasers directly on microchips, a breaktrhrough that will enable the mass-production of inexpensive and robust microsystems that exceed the performance capabilities of current technologies.

Defense systems for instance, such as radar, communications, imaging and sensing payloads rely on a wide variety of microsystems devices. These diverse devices typically require particular substrates or base materials and different processing technologies specific to each application, preventing the integration of such devices into a single fabrication process. Integration of these technologies, historically, has required combining one microchip with another, which introduces significant bandwidth and latency limitations as compared to microsystems integrated on a single chip. Although many photonic components can now be fabricated directly on silicon, realizing an efficient laser source on silicon has proven to be very difficult.
Now, the engineers at UCSB showed it was possible to “grow” or deposit successive layers of indium arsenide material directly on silicon wafers to form billions of light-emitting dots known as “quantum dots.” This method of integrating electronic and photonic circuits on a common silicon substrate promises to eliminate wafer bonding, and has application in numerous military and civilian electronics where size, weight, power and packaging/assembly costs are critical.
laser on chipsDARPA’s Electronic-Photonic Heterogeneous Integration (E-PHI) program has successfully integrated billions of light-emitting dots on silicon to create an efficient silicon-based laser. The Defense Advanced Research Projects Agency (DARPA) is an agency of the United States Department of Defense responsible for the development of new technologies for use by the military.
This method of integrating electronic and photonic circuits on a common silicon substrate promises to eliminate wafer bonding, and has application in numerous military and civilian electronics where size, weight, power and packaging/assembly costs are critical“.“It is anticipated that these E-PHI demonstrator microsystems will provide considerable performance improvement and size reduction versus state-of-the-art technologies,” said Josh Conway, DARPA program manager for E-PHI. “Not only can lasers be easily integrated onto silicon, but other components can as well, paving the way for advanced photonic integrated circuits with far more functionality than can be achieved today.

Source: http://www.darpa.mil/

Cancer Detection In Its Earliest Stages

An international team of researchers led by Professor Romain Quidant from The Institute of Photonic Sciences (ICFO ) -Spain -, report on the successful development of a “lab-on-a-chip” platform capable of detecting protein cancer markers in the blood using the very latest advances in plasmonics, nano-fabrication, microfluids and surface chemistry. The device is able to detect very low concentrations of protein cancer markers, enabling diagnoses of the disease in its earliest stages. This cancer-tracking nano-device shows great promise as a tool for future cancer treatments, not only because of its reliability, sensitivity and potential low cost, but also because of its easy carry-on portable properties, which is foreseen to facilitate effective diagnosis and suitable treatment procedures in remote places with difficult access to hospitals or medical clinics.

Although very compact (only a few cm2), the lab-on-a-chip hosts various sensing sites distributed across a network of fluidic micro-channels that enables it to conduct multiple analyses. Gold nano-particles lie on the surface of the chip and are chemically programed with an antibody receptor in such a way that they are capable of specifically attracting the protein markers circulating in blood. When a drop of blood is injected into the chip, it circulates through the micro-channels and if cancer markers are present in the blood, they will stick to the nano-particles located on the micro-channels as they pass by, setting off changes in what is known as the “plasmonic resonance”. The device monitors these changes, the magnitude of which are directly related to the concentration/number of markers in the patient blood thus providing a direct assessment of the risk for the patient to develop a cancer.

Source: http://www.icfo.eu/

Plasmonics: Using Light In Metals To Carry Information

A recently discovered technology called plasmonics marries the best aspects of optical and electronic data transfer. By crowding light into metal structures with dimensions far smaller than its wavelength, data can be transmitted at much higher frequencies such as terahertz frequencies, which lie between microwaves and infrared light on the spectrum of electromagnetic radiation that also includes everything from X-rays to visible light to gamma rays. Metals such as silver and gold are particularly promising plasmonic materials because they enhance this crowding effect.

Using an inexpensive inkjet printer, University of Utah electrical engineers produced microscopic structures that use light in metals to carry information. This new technique, which controls electrical conductivity within such microstructures, could be used to rapidly fabricate superfast components in electronic devices, make wireless technology faster or print magnetic materials.

High-speed Internet and other data-transfer techniques rely on light transported through optical fibers with very high bandwidth, which is a measure of how fast data can be transferred. Shrinking these fibers allows more data to be packed into less space, but there’s a catch: optical fibers hit a limit on how much data they can carry as light is squeezed into smaller and smaller spaces. In contrast, electronic circuits can be fashioned at much smaller sizes on silicon wafers. However, electronic data transfer operates at frequencies with much lower bandwidth, reducing the amount of data that can be carried.

Very little well-developed technology exists to create terahertz plasmonic devices, which have the potential to make wireless devices such as Bluetooth – which operates at 2.4 gigahertz frequency – 1,000 times faster than they are today,” says Ajay Nahata, a University of Utah professor of electrical and computer engineering and senior author of the new study.

The study has been published online in the journal Advanced Optical Materials.
Source: http://unews.utah.edu/

Bubbles Open The Doors For Next-Generation Displays

To combine the speed of optical communication with the portability of electronic circuitry, researchers use nanoplasmonics — devices that use short electromagnetic waves to modulate light on the nanometer scale, where conventional optics do not work. However, aiming and focusing this modulated light beam at desired targets is difficult. A research team from the Pennsylvania State University (Penn State) has find a new way to bend light beams to your whim. A few tiny liquid bubbles may be all that is necessary to open the doors for next-generation, high-speed circuits and displays. The main advantage of a bubble lens is just how quickly and easily researchers can reconfigure the bubble’s location, size, and shape — all of which affect the direction and focus of any light beam passing through it.

refraction pattern
Laboratory images of a light beam without a bubble lens, followed by three examples of different bubble lenses altering the light

There are different solid-state devices to control (light beams), to switch them or modulate them, but the tenability and reconfigurability are very limited,” said Tony Jun Huang, associate professor of engineering science and mechanics. “Using a bubble has a lot of advantages
Source: http://news.psu.edu/

Very Cheap Polymer Solar Cells

Researchers from Ulsan National Institute of Science and Technology – Korea – (UNIST) demonstrated high-performance polymer solar cells (PSCs) with power conversion efficiency (PCE) of 8.92% which is the highest values reported to date for plasmonic PSCs using metal nanoparticles (NPs).
This is the first report introducing metal NPs between the hole transport layer and active layer for enhancing device performance. The multipositional and solutions-processable properties of our surface plasmon resonance (SPR) materials offer the possibility to use multiple plasmonic effects by introducing various metal nanoparticles into different spatial location for high-performance optoelectronic device via mass production techniques.” said Prof. Jin Young Kim who led the study with Prof.Soojin Park from UNIST. “Our work is meaningful to develop novel metal nanoparticles and almost reach 10% efficiency by using these materials. If we continuously focus on optimizing this work, commercialization of PSCs will be a realization but not dream,” added Prof. Park.

A polymer solar cell is a type of thin film solar cells made with polymers that produce electricity from sunlight by the photovoltaic effect. Most current commercial solar cells are made from a highly purified silicon crystal. The high cost of these silicon solar cells and their complex production process has generated interest in developing alternative photovoltaic technologies.

Source: http://www.unist.ac.kr

Ultra-sensitive Tool for DNA analysis, thanks to Ancient Roman Cup

Utilizing optical characteristics first demonstrated by the ancient Romans, researchers at the University of Illinois at Urbana-Champaign have created a novel, ultra-sensitive tool for chemical, DNA, and protein analysis..plasmon resonance sensor
With this device, the nanoplasmonic spectroscopy sensing, for the first time, becomes colorimetric sensing, requiring only naked eyes or ordinary visible color photography,” explained Logan Liu, an assistant professor of electrical and computer engineering and of bioengineering at Illinois. “It can be used for chemical imaging, biomolecular imaging, and integration to portable microfluidics devices for lab-on-chip-applications“. His research team’s results were featured in the cover article of the inaugural edition of Advanced Optical Materials (AOM, optical section of Advanced Materials).

Roman Cup
Lycurgus cups were created by the Romans in 400 A.D. Made of a dichroic glass, the famous cup exhibits different colors depending on whether or not light is passing through it; red when lit from behind and green when lit from in front. It is also the origin of inspiration for all contemporary nanoplasmonics research—the study of optical phenomena in the nanoscale vicinity of metal surfaces.
Source: http://engineering.illinois.edu/


A Northwestern University research team has found a way to manufacture single laser devices that are the size of a virus particle and that operate at room temperature. These plasmonic nanolasers could be readily integrated into silicon-based photonic devices, all-optical circuits and nanoscale biosensors. Reducing the size of photonic and electronic elements is critical for ultra-fast data processing and ultra-dense information storage. The miniaturization of a key, workhorse instrument — the laser — is no exception. The results are published in the journal Nano Letters.

“Coherent light sources at the nanometer scale are important not only for exploring phenomena in small dimensions but also for realizing optical devices with sizes that can beat the diffraction limit of light,” said Teri Odom , a nanotechnology expert who led the research.

Source: http://www.northwestern.edu/

How To Diagnose Lung Diseases at Early Stage

Severe lung diseases are among the leading causes of death worldwide. To date they have been difficult to diagnose at an early stage. Within an international collaboration scientists from Munich- Germany – now developed an X-ray technology to do just that. Now they are working on bringing the procedure into medical practice.
X-Ray Nanotechnology.
A combination of dark-field and conventional transmission information allows for a clear distinction of healthy versus emphysematous tissue and an assessment of the regional distribution of the disease. From such images, a doctor might in future not only see if a patient is diseased but also which parts of the lung are affected and how much.
Especially in early stages of the disease, identification, precise quantification and localization of emphysema through the new technology would be very helpful”, says Professor Maximilian Reiser, head of the Institute for Clinical Radiology at Ludwig-Maximilians-University Munich.

Source: http://www.munich-photonics.de

Electronics without Current

Researchers at Tampere University of Technology, Finland, will explore paths toward a completely new way of designing and making logic circuits that consume no current and can be written and read with light. The key idea behind the project is the so-called quantum dot cellular automaton (QCA). In QCAs, pieces of semiconductor so small that single electronic charges can be measured and manipulated are arranged into domino like cells. Like dominos, these cells can be arranged so that the position of the charges in one cell affects the position of the charges in the next cell, which allows making logical circuits out of these “quantum dominos”. But, no charge flows from one cell to the next, i.e. no current. This, plus the extremely small size of QCAs, means that they could be used to make electronic circuits at densities and speeds not possible now. However, realisation of the dots and cells and making electrical connections to them has been a huge challenge.
Professors Donald Lupo from Department of Electronics, Mircea Guina and Tapio Niemi from Optoelectronics Research Centre (ORC), and Nikolai Tkachenko and Helge Lemmetyinen from Department of Chemistry and Bioengineering, want to investigate a completely new approach. They want to attach tailor-made molecules, optical nanoantennas, to the quantum dots, which can inject a charge into a dot or enable charge transfer between the dots when light of the right wavelength shines on them.
Laser light is emitted from the end of a cadmium sulfide nanowire.

Simultaneously, researchers at the University of Pennsylvania have made an important advance in this frontier of photonics, fashioning the first all-optical photonic switch out of cadmium sulfide nanowires. Moreover, they combined these photonic switches into a logic gate, a fundamental component of computer chips that process information. The research was conducted by associate professor Ritesh Agarwal and graduate student Brian Piccione of the Department of Materials Science and Engineering in Penn’s School of Engineering and Applied Science. Post-doctoral fellows Chang-Hee Cho and Lambert van Vugt, also of the Materials Science Department, contributed to the study.
Source: http://www.tut.fi/en/current/electronics-without-current-finnish-team-to-research-the-future-of-nanoelectronics-p032013c2

How to Weld Nanowires With Light

One area of intensive research at the nanoscale is the creation of electrically conductive meshes made of metal nanowires. Promising exceptional electrical throughput, low cost and easy processing, engineers foresee a day when such meshes are common in new generations of touch-screens, video displays, light-emitting diodes and thin-film solar cells.At the heart of the technique is the physics of plasmonics, the interaction of light and metal in which the light flows across the surface of the metal in waves, like water on the beach.

When two nanowires lie crisscrossed, we know that light will generate plasmon waves at the place where the two nanowires meet, creating a hot spot. The beauty is that the hot spots exist only when the nanowires touch, not after they have fused. The welding stops itself. It’s self-limiting,” explained Mark Brongersma, an associate professor of materials science engineering at Stanford and an expert in plasmonics. Brongersma is one of the study’s senior authors.
The rest of the wires and, just as importantly, the underlying material are unaffected,” noted Michael McGehee, a materials engineer and also senior author of the paper. “This ability to heat with precision greatly increases the control, speed and energy efficiency of nanoscale welding.”

Source: https://engineering.stanford.edu/news/stanford-engineers-weld-nanowires-light