News

Ninva Shamoun and Michael Andersson awarded the Microwave Road Stipend

2013-05-02T11:00:00Z

The prize ceremony was held at the workshop Swedish Antenna Veterans’ Day in association with EuCAP 2013, the 11th of April. The scholarship amount is 10 000 SEK.

The students have been attending the Wireless, Photonics and Space Engineering Master Program at Chalmers. Microwave Road is a national cluster focusing on international technology and market development uniting industry, universities, research institutes and regional and national public authorities.

Above: Ninva Shamoun and Michael Andersson with the chairman of Microwave Road, Ingmar Andersson.

More information about Microwave Road:
www.microwaveroad.se

More information about the Wireless, Photonics and Space Engineering Master's Program

Per-Simon Kildal awarded ERC Advanced Grant

2012-10-14T22:00:00Z

Per-Simon Kildal is congratulated for a 25 MSEK ERC Advanced Grant for research in "Waveguide-type semiconductor integrated circuits (ICs) in gaps between conducting surfaces with texture – architecture, electromagnetic modeling and micromachining".

Serguei Cherednichenko awarded ERC Starting Grant

2012-09-13T22:00:00Z

The proposed project is devoted to the research in the field of low noise and broadband Terahertz (THz) detectors/mixers. Such devices will be the key components for the next generation terahertz (or far infrared, FIR) high spectral resolution terahertz radio astronomical instruments (frequencies 1.5-10THz). The uniqueness of this frequency range is: large number of molecular gas lines; observation only from space based platforms are possible due to large atmospheric absorption; heterodyne receiver technology is immature with performance behind the required level. Currently, low noise mixers for frequencies above 1THz are Hot-Electron Bolometer (HEB) mixers based on NbN superconducting films. Due to the finite electron energy relaxation time the intermediate frequency bandwidth of NbN HEB mixers is limited to 3GHz, which results in a drastic sensitivity degradation at higher intermediate frequencies.

In this project we will investigate HEB mixers based on MgB2 (magnesium deboride) thin films. According to our preliminary study, MgB2 HEB mixers can provide a gain bandwidth of about 10GHz, i.e. at least double as wide as the present NbN film based counterparts. We will develop a deposition process for ultrathin MgB2 films on substrates both for quasioptical and waveguide based mixers. We will design and fabricated MgB2 mixers and investigate their performance up to 4THz.

ERC grant to web-security project

2012-09-01T22:00:00Z

The world wide web infrastructure is particularly exposed, where allowing the mere possibility of fetching a web page opens up opportunities to deliver potentially malicious executable content past current security mechanisms such as firewalls. A critical challenge is to secure the computing infrastructures without losing the benefits of the trends.

‒ It is our firm belief that the attacks will continue to succeed unless a fundamental security solution is devised, says Andrei Sabelfeld, professor in the Department of Computer Science and Engineering.

Andrei Sabelfeld has been awarded a Consolidator Grant by the European Research Council, for the project ProSecuToR. ERC Consolidator Grants are designed to support researchers at the stage at which they are consolidating their own independent research team or programme. The scheme will strengthen independent and excellent new individual research teams that have been recently created.

‒ ProSecuToR provides a unique and exciting opportunity to provide a foundation for web application security, and address the web security problem in its entirety – from the formal security model to concrete case studies, says Andrei Sabelfeld.

Language-based security is an innovative approach for enforcing security by construction, and ProSecuToR will develop the technology of programming language-based security in order to secure computing infrastructures. The project aims to deliver policies and enforcement mechanisms for protecting who can see and who can modify sensitive data. Security policies will be expressible by the programmer at the construction phase. Automatic enforcement mechanisms will prevent dangerous programs from executing whenever there is a possibility of compromising desired security properties.

The official start date for ProSecuToR is January 1, 2013.
The ERC Grant provides 1,5million Euro during 5 years.

For further information please contact Andrei Sabelfeld, Department of Computer Science and Engineering.
E-mail: andrei@chalmers.se
Phone: 031-772 10 18

Information regarding ERC Consolidator Grants

Anders Larsson receives an HP Labs Innovation Research Award

2012-08-23T22:00:00Z

Reserachers involved in the project Jörgen Bengtsson, Erik Haglund, Anders Larsson, Johan Gustafsson and Åsa Haglund. Photography: Peter Widing

High Contrast Grating VCSELs for WDM Computer Interconnects

The vertical cavity surface emitting laser (VCSEL) is the primary light source for short-reach optical communication because of high efficiency, excellent high speed properties, efficient coupling to optical fibers, and low manufacturing cost. It is today produced in large volumes for high capacity optical interconnect cables in storage area networks (datacenters) and high performance computing systems (computer clusters, supercomputers). In the near future, high speed optical cables with VCSEL-based optical transmitters will also make their debut in consumer electronics (Thunderbolt, USB, HDMI, etc.).

For computing applications, the small footprint and high modulation speed of VCSELs enable very high density and very high capacity interconnects. To increase capacity beyond what can be provided by a single channel, space division multiplexing (parallel fiber ribbons or multicore fibers) or wavelength division multiplexing (WDM) can be used. WDM, which requires monolithic multi-wavelength VCSEL arrays, enables optical interconnect architectures which offer more complex interconnect topologies and routing schemes. It also enables the interconnect network to adapt to irregular and time varying traffic patterns.

The project aims to develop a VCSEL technology whereby the wavelength of individual VCSELs can be set in a post-growth fabrication process, thereby enabling the realization of low power consumption, high speed, multi-wavelength VCSEL arrays for future WDM interconnects in computing systems.

Jörgen Blennow: Behöver civilingenjörsutbildningen i elektroteknik förändras radikalt?

2012-08-15T22:00:00Z

Läs artiklen i Elektronik Tidningen

Initiative Seminar: Green Information and Communication Technologies

2012-06-26T22:00:00Z

The transformation from an industrial society to an information and communication technology society has led to a dramatic change in our energy needs and in how energy is consumed. On the one hand ICT has become a major consumer in the vast computing and communication infrastructures that feed the web. At the same time our thirst for ICT also places increasing demands on power-efficiency in the very smallest of devices. On the other hand, ICT can harnessed to save huge amounts of energy by making hardware, software and communications smarter and more energy efficient.
In this ICT initiative seminar at Chalmers, we are presenting some hot topics in energy-aware computing and communication. We wish to address both the technical challenges as well as the impact on society.
Increased energy efficiency can be tackled through new components, smarter systems, and the way we use ICT. The seminar will explore such issues, from wireless communication to power-hungry data centers

View our programme Green ICT 2012.PDF

Register before October 1st at this link.

Welecome!

Professor Erik Ström is interviewed by Forskning & Framsteg

2012-06-07T22:00:00Z

Professor Erik Ström is interviewed by ”Forskning & Framsteg”:
”Mobilnätets motorvägar tål inte mobiler” (Forskning &Framsteg 3/2012.)
(”The highways of the cell phone networks cannot cope with the demands of the mobile phones”)

Read the article.

Giant telescope Alma to be upgraded with Swedish technology

2012-06-05T15:00:00Z

The oversight board for Alma has authorised the design and building of an additional set of receivers, which will enable the telescope to access a part of the spectrum of light that it cannot currently study. The receivers will be built by an international consortium in which Chalmers and Onsala Space Observatory play key roles.

Hans Olofsson, professor of radio astronomy at Chalmers and director of Onsala Space Observatory, is delighted by the new task.

“We´re very pleased to be involved in making Alma one of the biggest and best observatories of our time. The contract is worth 50 million SEK for Chalmers over 5 years. During the period Alma is under construction a total of 180 million SEK will be returned to Sweden in the form of contracts”, he says.

Alma – the Atacama Large Millimeter/submillimeter Array – is the world’s largest astronomy project. This powerful new facility on the Chajnantor plateau in Chile is giving astronomers insight both into how the Universe and its galaxies have evolved since the Big Bang, and how stars and planetary systems formed in our own galaxy. Although only half of its final total of 66 antennas are currently in place at high altitude in northern Chile, Alma is already operating and making scientific observations with a partial array.

“Alma´s first discoveries have already given us a taste of what awaits us when the telescope is completed in 2013. But we won´t stop there. These new receivers will make it possible for us to take even better advantage of Alma´s fantastic site on Chajnantor”, says Wolfgang Wild, European project manager for Alma.

The new receivers were originally designed, developed, and prototyped by Onsala Space Observatory´s Advanced Receiver Development group, based at Chalmers. Six of these receivers have already been built and supplied to Alma (see previous press release, December 2010).

One of the first six “Band 5” receiver cartridges built for Alma. Extremely weak signals from space are collected by the Alma antennas and focused onto the receivers, which transform the faint radiation into an electrical signal.

Photo: Onsala Space Observatory/Alexey Pavolotsky

Over the next five years, all 66 of Alma´s antennas will be equipped with these new receivers. To do this, including spares, another 67 units need to be built.

“Our role will be to, together with our colleagues in the Netherlands, manufacture 67 new receivers that are just as sensitive as the six that we have already built in our lab in Gothenburg”, says Victor Belitsky, professor of radio and space science at Chalmers, who will be technical lead for the consortium.

The receivers will be used to study some of the earliest galaxies in the Universe and will help us to understand when some of the first stars formed. They will also enhance astronomers´ abilities to measure the presence of water – a molecule essential to life – in the dusty disks where planets are believed to form, and in the atmospheres of planets and comets in our own Solar System.

Water in space can be tricky to measure accurately, because of the confusing effects of observing through the water vapour in Earth´s atmosphere. The way in which Alma´s “Band 5” receivers will measure water reduces some of these difficulties.

The decision to fund this enhancement of Alma, even before the telescope is completed, was made by the Alma Board in April 2012. On 9 May 2012, the decision was approved by ESO´s Finance Committee. The upgrade is expected to be completed in 2016.

More about the receivers

Chalmers scientists are producing the new receivers in collaboration with the Rutherford Appleton Laboratory, UK, and the European Southern Observatory (ESO), under the European Commission (EC) supported Framework Programme FP6 (Alma Enhancement), starting in 2006. Six of these receivers have been built under the FP6 contract and supplied to Alma.

The 67 new units will be built by Europe with contributions from the United States. ESO will place the European contract for the cryogenically cooled receivers, and oversee their development. The consortium leader will be Nova, the research school for astronomy in the Netherlands. The receivers will be fabricated by Nova in partnership with Onsala Space Observatory´s Advanced Receiver Development group. In North America, the National Radio Astronomy Observatory (NRAO) will build the high-precision oscillators that will tune the receivers, so that the output from all antennas can be precisely combined to make high-resolution images.

More about Alma (Atacama Large Millimeter/submillimeter Array)

Alma, an international astronomy facility, is a partnership of Europe, North America and East Asia in cooperation with the Republic of Chile. Alma construction and operations are led on behalf of Europe by ESO, on behalf of North America by the National Radio Astronomy Observatory (NRAO), and on behalf of East Asia by the National Astronomical Observatory of Japan (NAOJ). The Joint Alma Observatory (JAO) provides the unified leadership and management of the construction, commissioning and operation of Alma.

Alma observes the Universe in radio waves: light which is invisible to our eyes. Extremely weak signals from space are collected by the Alma antennas and focused onto the receivers, which transform the faint radiation into an electrical signal. The new “Band 5” receivers will be able to detect electromagnetic radiation with wavelengths between about 1.4 and 1.8 millimeters (211 and 163 gigahertz), one of the ranges of the spectrum to which Earth´s atmosphere is partially transparent, which allows the light to reach the Alma antennas.

More about Onsala Space Observatory

Onsala Space Observatory is Sweden´s national facility for radio astronomy. The observatory provides researchers with equipment for the study of the Earth and the rest of the universe. It operates two radio telescopes in Onsala, 45 km south of Gothenburg, and participates in several international projects. The Department of Space and Earth Science at Chalmers University of Technology hosts the observatory, which is operated on behalf of the Swedish Research Council.

For more information and images please contact:

Robert Cumming, astronomer and communications officer, Onsala Space Observatory, +46 31 772 55 00 or +46 704 93 31 14, robert.cumming@chalmers.se

Victor Belitsky, Professor of Radio and Space Science at Chalmers University of Technology, leader of the Group for Advanced Receiver Development, +46 31 772 18 93, victor.belitsky@chalmers.se

The giant telescope Alma is now more than halfway to completion, with 39 of 66 antennas in place on the Chajnantor plateau in the Atacama desert in northern Chile. Alma is the world’s most complex ground-based telescope, expected to be completed in 2013. Pictures: the European Southern Observatory (ESO)

ICT researcher Ulf Assarsson describes computer graphics on TV 4

2012-06-04T22:00:00Z

Associate Professor Ulf Assarsson, Head of Research Group Graphics, describes his research in shadow algorithms - both real-time and non real-time - for hard and soft shadows including shadows in hair, fur and smoke.

View the interview TV4 News Vetenskap, at this link (t = 17 min into the programme).

PhD students Markus Billeter , Ola Olsson, Erik Sintorn, Viktor Kämpe are also interviewed.

Space probes will be more useful with amplifiers from Chalmers

2012-04-26T06:00:00Z

The research group has developed and built 30 ultrasensitive, cryogenically cooled amplifiers for receiving satellite signals. They will be used, for example, in the receiver of the Cebreros tracking station, which will be upgraded within a few weeks. Cebreros provides daily information on the space projects Venus Express, Mars Express and Rosetta.

ESA's satellites investigate and monitor atmospheric changes on the Earth, for example. Their space probes collect data on the solar system, the planets as well as comets. The signals from satellites and space probes are received by antennas installed in various places around the surface of the Earth so that signals can be received regardless of the Earth's rotation. The amplifier is one of the most important building blocks of these antennas and determines the quality of the entire receiver chain.

The new amplifiers from Chalmers have several advantages over their predecessors. Their primary benefit is that they add less noise to the satellite signal, which enables major possibilities for space research.

"Communication is more reliable," says Piotr Starski, one of the Chalmers' researchers who have developed the amplifiers. "Satellite availability will also be improved since it will be possible to follow them farther down toward the horizon where atmospheric noise contribution increases."

The additional noise in the amplifiers is referred to as the noise temperature, NT, and is measured in Kelvin (K). The new amplifiers have a noise temperature of just 4 K.

"This is exceptionally good for this type of circuit, nearly state-of-the-art," says Piotr Starski. "We have also had a more modern approach to the design which has enabled us to make much smaller and less expensive amplifiers than their predecessors."

The amplifiers are built with so called Monolithic Microwave Integrated Circuits (MMIC), which means that they are complete components that are much easier to assemble. Previously it was not possible to build cooled MMIC amplifiers that performed adequately. But researchers at Chalmers have achieved performance that is as good as that of hybrid amplifiers, which are much more expensive and complicated to produce.

Production of the amplifiers has been done in collaboration with Low Noise Factory, a start-up company from Chalmers. The reason that ESA ordered the amplifiers from Chalmers is that the Microwave Electronic Laboratory at Chalmers is one of a very few places in the world that is capable of developing cryogenically cooled amplifiers with extremely low noise and adequate performance, especially as MMIC.

Watch an animation that shows how the Chalmers-made amplifiers will be used in the antenna dish Cebreros:
http://www.chalmers.se/sv/forskning/forskning-i-framkant/Sidor/Mikrovågsteknik.aspx

For more information please contact:
Niklas Wadefalk, Department of Microtechnology and Nanoscience, +46 31- 772 1730, niklas.wadefalk@chalmers.se

Piotr Starski, Department of Microtechnology and Nanoscience, +46 31-772 1734, piotr.starski@chalmers.se

SEK 50 million for new research infrastructure

2012-04-23T13:00:00Z

The Knut and Alice Wallenberg Foundation is the largest private financier of research in Sweden. In 2012, the foundation will concentrate on life science and nanotechnology – two of Chalmers' Areas of Advance.

Better nanoscale fabrication
Chalmers Nanofabrication Laboratory will receive SEK 22 million that will be used for new nanolithography equipment. The funds will primarily be used for a new electron beam lithography (EBL) system, which is a technology used to produce electronics components and other nanosized structures. The technology is very important within nanotechnology and has been a prerequisite for several important research breakthroughs from Chalmers recently (use the links below to see examples).

Chalmers is the node for electron beam lithography within Myfab, the Swedish national research infrastructure.

"The grant will allow us to purchase the latest technology to ensure that Swedish nanotechnology research stays at the cutting edge of development," says Peter Modh, Department Head at the Nanofabrication Laboratory. "Amongst other things, we will be able to use the equipment to cut the size of the smallest producible features in half.”

Capacity will also increase, for example, by another person being employed for electron beam lithography. This is important since an increasing number of research projects need to use the technology, at the same time there is a need on the part of industry to use the equipment at Chalmers.

The Nanofabrication Laboratory at Chalmers is one of the most advanced clean room laboratories in the university world. It will now be equipped with new technology for nanolithography.

Photo: Jan-Olof Yxell, Chalmers

New radio telescopes to measure how the Earth moves
Onsala Space Observatory will receive SEK 29.7 million to build two new radio telescopes. Together they will measure the Earth's movements more precisely than previously, using galaxies in the distant universe to determine the position of the telescopes. The measurements will then be used by scientists studying the interplay between the Earth's interior, its crust, atmosphere, oceans and climate.

"The two antennas, each 12 metres in diameter, will work together in a network of similar telescopes currently being built and planned all over the world," says Robert Cumming, astronomer and communication officer at Onsala Space Observatory. "By observing galaxies billions of light years away, the twin telescope and its siblings around the world will be able to determine their positions on the Earth – and in space – with ten times better precision than is possible today.

The technology is known as geodetic VLBI (Very Long Baseline Interferometry).

Image montage showing what the twin telescope might look like on site at Onsala Space Observatory.

Image: Onsala Space Observatory/Västkustflyg. Antennas: NASA/GSFC/Elizabeth Zubritsky

Study of disease patterns and basic biological processes
Chalmers will also receive part of a third grant totalling SEK 38.7 million together with the Swedish University of Agricultural Sciences and Umeå University. The grant will be used for metabolite analysis equipment and for performing the analyses. The analyses help produce detailed information on all the small molecules involved in cell metabolism, which enables unique patterns to be discovered for a specific disease and promotes understanding of basic biological processes. Chalmers will share its research through Professor Jens Nielsen's advanced modelling group.

Facts about the Knut and Alice Wallenberg Foundation
Over the past five years, the Knut and Alice Wallenberg Foundation has disbursed SEK 4.8 billion to promote Swedish research and researchers. For this year's decision round, the foundation has earmarked SEK 352 million for research infrastructure. Of that amount, SEK 220 million will go to life science and medicine and SEK 88 million to nanoscience.
Read more about the foundation

Read more about the Onsala Space Observatory's research and equipment:
http://www.chalmers.se/rss/oso-en/about-us/research7904
http://www.chalmers.se/rss/oso-en/about-us/research

Read more about research results that are based on electron beam lithography:
http://www.chalmers.se/en/news/Pages/Chalmers-scientists-create-light-from-vacuum.aspx
http://www.chalmers.se/en/news/Pages/Quantum-microphone-captures-extremely-weak-sound.aspx

For more information please contact:
Robert Cumming, Onsala Space Observatory, +46 31-772 55 00, +46 70-49 33 114, robert.cumming@chalmers.se
Gunnar Elgered, Department of Earth and Space Sciences, +46 31-772 55 65, +46 31-772 16 10, gunnar.elgered@chalmers.se
Peter Modh, Nanofabrication Laboratory, +46 31-772 16 05, peter.modh@chalmers.se

Quantum microphone captures extremely weak sound

2012-02-06T09:00:00Z

The “quantum microphone” is based on a single electron transistor, that is, a transistor where the current passes one electron at a time. The acoustic waves studied by the research team propagate over the surface of a crystalline microchip, and resemble the ripples formed on a pond when a pebble is thrown into it. The wavelength of the sound is a mere 3 micrometers, but the detector is even smaller, and capable of rapidly sensing the acoustic waves as they pass by.

On the chip surface, the researchers have fabricated a three-millimeter-long echo chamber, and even though the speed of sound on the crystal is ten times higher than in air, the detector shows how sound pulses reflect back and forth between the walls of the chamber, thereby verifying the acoustic nature of the wave.

The detector is sensitive to waves with peak heights of a few percent of a proton diameter, levels so quiet that sound can be governed by quantum law rather than classical mechanics, much in the same way as light.

"The experiment is done on classical acoustic waves, but it shows that we have everything in place to begin studies of proper quantum-acoustics, and nobody has attempted that before", says Martin Gustafsson, PhD student and first author of the article.

Apart from the extreme quietness, the pitch of the waves is too high for us to hear: The frequency of almost 1 gigahertz is 21 octaves above one-lined A. The new detector is the most sensitive in the world for such high-frequency sound.

Read the article in Nature Physics

The authors of the article are Martin Gustafsson, Göran Johansson and Per Delsing from Chalmers University of Technology, Gothenburg, Sweden, and Paulo Santos from the Paul Drude Institute, Berlin, Germany. Martin Gustafsson will defend his doctoral thesis in April.

Caption: A "quantum microphone" based on a Single Electron Transistor (SET) detects sound waves on a chip surface, so called Surface Acoustic Waves (SAW). The waves make the charge of the atoms underneath the quantum microphon oscillate. Since the quantum microphone is an extremely sensitive charge detector, very low sound levels can be detected. (The size of the waves are exaggerated in the picture). Picture: Philip Krantz, Chalmers

For more information, please contact
Martin Gustafsson, +46 70-745 9955, martin.gustafsson@chalmers.se
Göran Johansson, +46 73-060 7338, goran.l.johansson@chalmers.se
Per Delsing, +46 70-308 8317, per.delsing@chalmers.se

Paulo Santos, +49-30-20377-221, santos@pdi-berlin.de

Graphene mixer can speed up future electronics

2012-01-01T23:00:00Z

A mixer is a key building block in all electronic systems – a device that combines two or more electronic signals into one or two composite output signals. Future applications at THz frequencies such as radar systems for security and safety, radio astronomy, process monitoring and environmental monitoring will require large arrays of mixers for high-resolution imaging and high-speed data acquisition. Such mixer arrays or multi-pixel receivers need new type of devices that are not only sensitive but also power-efficient and compact.

The ability in graphene to switch between hole or electron carrier transport via the field effect enables a unique niche for graphene for RF IC applications. Thanks to this symmetrical electrical characteristic, the researchers at Chalmers have managed to build the G-FET subharmonic resistive mixer using only one transistor. Hence, no extra feeding circuits are required, which makes the mixer circuit more compact as opposed to conventional mixers. As a consequence, the new type of mixer requires less wafer area when constructed and can open up for advanced sensor arrays, for example for imaging at millimetre waves and even sub millimetre waves as G-FET technology progress.

- “The performance of the mixer can be improved by further optimising the circuit, as well as fabricating a G-FET device with a higher on-off current ratio”, says Jan Stake, professor of the research team. “Using a G‐FET in this new topology enables us to extend its operation to higher frequencies, thereby exploiting the exceptional properties of graphene. This paves the way for future technologies operating at extremely high frequencies.”

Schematic picture of a subharmonic graphene-FET mixer. The LO and RF signals are fed to the gate and drain terminals, respectively, and the IF signal is extracted from the drain terminal.

In addition to enabling compact circuits, the G-FET provides potential to reach high frequencies thanks to the high velocity in graphene, and the fact that a subharmonic mixer only requires half the local oscillator (LO) frequency compared to a fundamental mixer. This property is attractive especially at high frequencies (THz) where there is a lack of sources providing sufficient LO-power.

Moreover, the G-FET can be integrated with silicon technology. For example, it is CMOS compatible (Complementary Metal Oxide Semiconductor) and among other things it can be used in CMOS electronics for backend processing on a single chip.

Graphene, that was first produced in 2004, has rapidly gone from curiosity‐driven to applied research. Read more about the active research into graphene at Chalmers:
http://www.chalmers.se/en/news/Pages/Millions-in-research-to-take-graphene-out-of-the-lab.aspx

For more information, please contact:
Jan Stake, Department of Microtechnology and Nanoscience, Chalmers University of Technology, +46 31 772 49 83, jan.stake@chalmers.se

The work is published in IEEE Electron Device Letters.
Open access version

Swedish Foundation of Strategic Research (SSF) supported the work.

One of the most important physics breakthroughs of 2011 took place at Chalmers

2011-12-15T23:00:00Z

Per Delsing, Göran Johansson and Christopher Wilson at the Institution for microtechnology and nanoscience. Photo: Jan-Olof Yxell and Per Delsing

Physics World is the world's leading physics magazine and the award was founded in 2009. The magazine says:

“Christopher Wilson and colleagues of Chalmers University of Technology in Sweden together with physicists in Japan, Australia and the US have bagged fifth place because they are the first to see the dynamical Casimir effect in the lab. The effect arises when a mirror is moving so quickly through a vacuum that pairs of virtual photons – which are always appearing and then annihilating – are pulled apart to create real photons that can then be detected. As well as shedding new light on the Casimir effect, the team's use of a superconducting quantum interference device (SQUID) as the mirror make this an extremely clever experiment.”

The top 10 breakthroughs list has been compiled by the Physics World team, who reviewed over 350 news articles about breakthroughs in the physical sciences published on physicsworld.com in 2011. The criteria for judging included:
•        Fundamental importance of research
•        Significant advance in knowledge
•        Strong connection between theory and experiment
•        General interest to all physicists

Update december 22: The news item "Moving mirrors make light from nothing" was the most popular story from 2011 at the site Nature News. Thus, it had more readers than the CERN news that neutrinos can travel faster than light. See the complete list of the most read news stories of 2011 here.

Read the complete Physics World´s list of top 10 breakthroughs for 2011:
http://physicsworld.com/cws/article/news/48126

Read the news item ”How to turn darkness into light” in Physics World:
http://physicsworld.com/cws/article/news/47856

Read the press release ”Chalmers scientists create light from vacuum”:
http://www.chalmers.se/en/news/Pages/Chalmers-scientists-create-light-from-vacuum.aspx

ERC Advanced Grant awarded to Professor Peter Andrekson

2011-12-08T23:00:00Z

ERC "Advanced Grants" fund cutting-edge research by the very best established research leaders in Europe. According to the Council’s website, projects funded by these competitive and selective grants must be highly ambitious, pioneering, and creative in their approach. The grants support research that takes risks, employing unconventional methodologies and investigations “at the interface between established disciplines” and presenting the possibility of a major breakthrough with far-reaching impact.

Optical amplifiers are essential in optical communication systems as they compensate loss induced by the transmission fiber ensuring signal integrity of the information being transmitted, as well as in other applications such as spectroscopy.

This research project deals with phase-sensitive optical parametric amplifiers (PSA) that have unique and superior properties compared with all other optical amplifiers, most notably the potential of noiseless amplification, very broad optical bandwidth, and being an enabler of a range of ultrafast all-optical functionalities. In communication, there is an urgent need to develop new technologies that can break the „nonlinear Shannon capacity limit‟, which is considered a serious barrier for continued capacity increase needed to meet the exponentially growing demand for bandwidth. The use of PSAs is expected to be an essential part of this development.

The objective is to unleash the unexplored potential of PSAs by generating knowledge and implementing experimental demonstrations that go substantially beyond current state-of-the-art. This involves a mix of engineering and scientific challenges with telecom and non-telecom applications in mind. We will leverage advances in other areas e.g. low loss photonic crystal fibers and highly nonlinear materials to realize compact PSAs with unprecedented performance.

Specifically, we will demonstrate:

• Significant merits (reach, spectral efficiency, capacity) of PSAs in optical transmission systems
• High coherence, low noise lasers by utilizing ultralow noise amplifier as gain element
• Very broad gain bandwidth, low noise PSAs using specially tailored nonlinear gain medium
• Compact (hybrid integration compatible) PSA using new nonlinear materials
• Novel ultrafast all-optical operations/signal processing using PSAs
• Capability of PSAs for detection of very weak optical signals for e.g. spectroscopy and quantum optics

Peter Andrekson appointed to Wallenberg Scholar

2011-12-08T23:00:00Z

Knut och Alice Wallenbergs Stiftelse (KAW) has selected Peter Andrekson to be one of the researchers within “Wallenberg Scholars”. This is a program with the aim of supporting and stimulating some of the most successful researchers at Swedish universities. Each Wallenberg Scholar will receive a five-year research grant of 3 MSEK per year.

KAW_Wallenberg_Scholars_2011.pdf

Carbon nanotubes best for 3D electronics

2011-12-08T23:00:00Z

Three dimensional integration is a hot field within electronics since it offers a new way to package components densely and thus build tiny, well-functioning units. When stacking chips vertically, the most effective way to interconnect them is with electrical interconnects that go through the chip (instead of being wired together at the edges) – what are known as through-silicon vias.

The industry thus far has primarily used copper for this purpose; however, copper has several disadvantages that can limit the reliability of 3D electronics. Another major issue involves cooling when the chips get hot. The excellent thermal qualities of carbon nanotubes can play a decisive role in this respect.

Thus a research team at Chalmers is working with carbon nanotubes as conductive material for through-silicon vias. Carbon nanotubes – or tubes made of graphene whose walls are only one atom thick – are going to be the most reliable of all conductive materials if it is possible to use them on a large scale. This is the opinion of Kjell Jeppsson, a member of the research team.

"Potentially, carbon nanotubes have much better properties than copper, both in terms of thermal and electrical conductivity”, he says. “Carbon nanotubes are also better suited for use with silicon from a purely mechanical point of view. They expand about the same amount as the surrounding silicon while copper expands more, which results in mechanical tension that can cause the components to break."

The researchers have demonstrated that two chips can be vertically interconnected with carbon nanotubes by through-silicon via interconnects, and that the chips can be bonded. They have also demonstrated that the same method can be used for electrical interconnection between the chip and the package.

Two chips have interconnects that are filled with thousands of carbon nanotubes. The chips are then bonded with adhesive so that the carbon nanotubes are directly contacted. A connection using two such interconnects is pictured to the right.
Image credit: Teng Wang, Kjell Jeppson, Lilei Ye, Johan Liu. Carbon-Nanotube Through-Silicon Via Interconnects for Three-Dimensional Integration. Small, 2011, Volume 7, pages 2,313–2,317. Copyright Wiley-VCH Verlag GmbH & Co. KGaA. Reproduced with permission.

PhD student Teng Wang – who defends his thesis on 12 December – has worked on production. He has developed a technique to fill through-silicon vias with thousands of carbon nanotubes. The chips are then bonded with an adhesive so that the carbon nanotubes are directly contacted and can thus conduct current through the chips.

"One difficulty involves producing carbon nanotubes with perfect properties and with the length we need to go through the chip," he says. "We have produced tubes that are 200 micrometers long, which can be compared to the diameter which is only 10 nanometers. Their properties, however, are not yet perfect."

For the method to be transferred to industrial production, manufacturing temperature needs to be reduced to a maximum of 450 degrees. This is a great challenge since carbon nanotubes are currently "grown" at a minimum of 700 degrees.

If successful, entirely new possibilities will arise for future shrinking of electronics – not least in terms of improved performance. The three dimensional integration using through-silicon vias provides significantly quicker signal transfers than traditional integration where chips are placed next to each other. Furthermore, through-silicon vias with carbon nanotubes provide less expensive production compared to the current technology that uses copper interconnects.

"There are several projects involving 3D integration underway in the industry, but there are potential problems with both cooling and reliability since they use copper," says Kjell Jeppsson. "If our method works on a large scale, I believe it will be in production within five years."

For more information please contact:
Kjell Jeppson, Department of Microtechnology and Nanoscience, +46 31-772 1856, kjell.jeppson@chalmers.se
Teng Wang, Department of Microtechnology and Nanoscience, +46 31-772 3092, teng.wang@chalmers.se
Johan Liu, Department of Microtechnology and Nanoscience, +46 31-772 3067, johan.liu@chalmers.se

The PhD thesis that is defended on December 12:

http://publications.lib.chalmers.se/cpl/record/index.xsql?pubid=148488

Read the researchers' articles in the scientific journals Small and Advanced Materials:

Carbon-Nanotube Through-Silicon Via Interconnects for Three-Dimensional Integration

Ultrafast Transfer of Metal-Enhanced Carbon Nanotubes at Low Temperature for Large-Scale Electronics Assembly

Assistant Professor Michail Matthaiou receives IEEE award

2011-12-01T23:00:00Z

The area of wireless communications has been rapidly developing over the past decade, and has had a substantial impact on our everyday lives, for example, wireless networking, video transfer and 4G. One of the key technologies behind this development has been multiple-input multiple-output (MIMO), where multiple antenna elements are deployed at both the transmitter and receiver.

The future is even more promising and challenging since the emerging applications, like smart phones, tablets, navigation and vehicular applications require faster, more reliable and more secure wireless links. In the long run, the convergence between wired and wireless technologies will allow operators or content providers, and eventually customers, to enjoy the complete functionalities and resources of the network.

Michail has been an Assistant Professor at the department of Signals and systems since June of 2010 and is currently leading the CHASE-MIMO Systems project funded by the Swedish Governmental Agency for Innovation Systems (VINNOVA), Ericsson AB and Qamcom AB. In May 2011, he obtained his Docent title on Multiple-Antenna Communication Systems.

Chalmers scientists create light from vacuum

2011-11-16T18:00:00Z

In the Chalmers scientists’ experiments, virtual photons bounce off a “mirror” that vibrates at a speed that is almost as high as the speed of light. The round mirror in the picture is a symbol, and under that is the quantum electronic component (referred to as a SQUID), which acts as a mirror. This makes real photons appear (in pairs) in vacuum. Illustration: Philip Krantz, Chalmers

The experiment is based on one of the most counterintuitive, yet, one of the most important principles in quantum mechanics: that vacuum is by no means empty nothingness. In fact, the vacuum is full of various particles that are continuously fluctuating in and out of existence. They appear, exist for a brief moment and then disappear again. Since their existence is so fleeting, they are usually referred to as virtual particles.

Chalmers scientist, Christopher Wilson and his co-workers have succeeded in getting photons to leave their virtual state and become real photons, i.e. measurable light. The physicist Moore predicted way back in 1970 that this should happen if the virtual photons are allowed to bounce off a mirror that is moving at a speed that is almost as high as the speed of light. The phenomenon, known as the dynamical Casimir effect, has now been observed for the first time in a brilliant experiment conducted by the Chalmers scientists.

“Since it’s not possible to get a mirror to move fast enough, we’ve developed another method for achieving the same effect,” explains Per Delsing, Professor of Experimental Physics at Chalmers. “Instead of varying the physical distance to a mirror, we've varied the electrical distance to an electrical short circuit that acts as a mirror for microwaves.”

The “mirror” consists of a quantum electronic component referred to as a SQUID (Superconducting quantum interference device), which is extremely sensitive to magnetic fields. By changing the direction of the magnetic field several billions of times a second the scientists were able to make the “mirror” vibrate at a speed of up to 25 percent of the speed of light.

“The result was that photons appeared in pairs from the vacuum, which we were able to measure in the form of microwave radiation,” says Per Delsing. “We were also able to establish that the radiation had precisely the same properties that quantum theory says it should have when photons appear in pairs in this way.”

What happens during the experiment is that the “mirror” transfers some of its kinetic energy to virtual photons, which helps them to materialise. According to quantum mechanics, there are many different types of virtual particles in vacuum, as mentioned earlier. Göran Johansson, Associate Professor of Theoretical Physics, explains that the reason why photons appear in the experiment is that they lack mass.

“Relatively little energy is therefore required in order to excite them out of their virtual state. In principle, one could also create other particles from vacuum, such as electrons or protons, but that would require a lot more energy.”

The scientists find the photons that appear in pairs in the experiment interesting to study in closer detail. They can perhaps be of use in the research field of quantum information, which includes the development of quantum computers.

However, the main value of the experiment is that it increases our understanding of basic physical concepts, such as vacuum fluctuations – the constant appearance and disappearance of virtual particles in vacuum. It is believed that vacuum fluctuations may have a connection with “dark energy” which drives the accelerated expansion of the universe. The discovery of this acceleration was recognised this year with the awarding of the Nobel Prize in Physics.

Read the paper “Observation of the dynamical Casimir effect in a superconducting circuit” in Nature

Listen to an interview with Christopher Wilson at Nature podcast

For further information, please contact:

Christopher Wilson, +1-213-215-8576, chris.wilson@chalmers.se
Per Delsing, +46 31 772 33 17, +46 70 308 83 17, per.delsing@chalmers.se
Göran Johansson, +46 31 772 32 37, +46 73 060 73 38, goran.L.johansson@chalmers.se

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