A device that looks like a tiny washboard may clean the clocks of current commercial products used to manipulate infrared light.
New research by the Rice University lab of Qianfan Xu has produced a micron-scale spatial light modulator (SLM) like those used in sensing and imaging devices, but with the potential to run orders of magnitude faster. Unlike other devices in two-dimensional semiconducting chips, the Rice chips work in three-dimensional "free space."
Xu and his Rice colleagues detailed their antenna-on-a-chip for light modulation this week in Nature's open-access, online journal Scientific Reports.
The manipulation of light has become central to the information economy. Think about light-reflecting compact discs and their video variants and all the ways lasers are used, from sensing to security to surgery. Light carries data through optical fibers for telecommunications and signals on the molecular scale as photonics techniques improve. Light-emitting diodes power television displays (for viewers clutching infrared remotes) and are beginning to replace the inefficient light bulbs in homes.
But in the computer space, light has been bound and gagged by two-dimensional circuitry, tied to waveguides that move it from here to there, Xu said. He and his colleagues point out in the new paper that 2-D systems fail to take advantage of "the massive multiplexing capability of optics" made possible by the fact that "multiple light beams can propagate in the same space without affecting each other."
The researchers see great potential for free-space SLMs in imaging, display, holographic, measurement and remote sensing applications.
Simply put, the Rice team's microscopic SLM chips are nanoscale ribs of crystalline silicon that form a cavity sitting between positively and negatively doped silicon slabs connected to metallic electrodes. The positions of the ribs are subject to nanometer-scale "perturbations" and tune the resonating cavity to couple with incident light outside. That coupling pulls incident light into the cavity. Only infrared light passes through silicon, but once captured by the SLM, it can be manipulated as it passes through the chip to the other side. The electric field between the electrodes turns the transmission on and off at very high speeds.
Individual SLMs are analogous to pixels, and Xu, an assistant professor of electrical and computer engineering, sees the possibility of manufacturing chips that contain millions of them.
In conventional integrated photonics, "You have an array of pixels and you can change the transmission of each pixel at a very high speed," he said. "When you put that in the path of an optical beam, you can change either the intensity or the phase of the light that comes out the other side.
"LED screens are spatial light modulators; so are micromirror arrays in projectors, in which the mirrors rotate," he said. "Each pixel changes the intensity of light, and you see an image. So an SLM is one of the basic elements of optical systems, but their switching speed is limited; some can get down to microseconds, which is okay for displays and projection.
"But if you really want to do information processing, if you want to put data on each pixel, then that speed is not good enough." Xu said the Rice team's device "can potentially modulate a signal at more than 10 gigabits per second.
"What we show here is very different from what people have been doing," he said. "With this device, we can make very large arrays with high yield. Our device is based on silicon and can be fabricated in a commercial CMOS factory, and it can run at very high speed. We think this can basically scale up the capability of optical information processing systems by an order of several magnitudes."
As an example, he suggested the device could give the single-pixel camera in development at Rice – which at the beginning took eight hours to process an image – the ability to handle real-time video.
"Or you could have an array of a million pixels, and essentially have a million channels of data throughput in your system, with all this signal processing in parallel," he said. "If each pixel only runs at kilohertz speeds, you don't get much of an advantage compared with microelectronic systems. But if each pixel is working at the gigahertz level, it's a different story."
Though Xu's antennas would not be suitable for general computing, he said, they could be capable of optical processing tasks that are comparable in power to supercomputers. "Optical information processing is not very hot," he admitted. "It's not fast-developing right now like plasmonics, nanophotonics, those areas. But I hope our device can put some excitement back into that field."
Co-authors of the paper are Rice graduate students Ciyuan Qiu, Jianbo Chen and Yang Xia.
The research was supported by the Air Force Office of Scientific Research.
Read the paper at http://www.nature.com/srep/2012/121114/srep00855/full/srep00855.html
This news release can be found online at news.rice.edu.
Follow Rice News and Media Relations via Twitter @RiceUNews
Xu Group at Rice: http://www.ece.rice.edu/ece/xugroup/
Images for download:
Rice University researchers have developed an antenna-on-a-chip for spatial light modulation that possible the manipulation of infrared light at very high speeds for signal processing and other optical applications. From left: graduate students Ciyuan Qiu, Jianbo Chen and Yang Xia, and Qianfan Xu, an assistant professor of electrical and computer engineering. (Credit: Jeff Fitlow/Rice University)
Crystalline silicon sits between two electrodes in a microscopic antenna-on-a-chip designed by researchers at Rice University. The chip, a spatial light modulator, couples with incident light and makes possible the manipulation of infrared light at very high speeds for signal processing and other optical applications. (Credit: Xu Group/Rice University)
An illustration shows the design of Rice University researchers' antenna-on-a-chip for spatial light modulation. The chip is able to process incident infrared light for signal processing at very high speeds. (Credit Xu Group/Rice University)
Located on a 300-acre forested campus in Houston, Rice University is consistently ranked among the nation's top 20 universities by U.S. News & World Report. Rice has highly respected schools of Architecture, Business, Continuing Studies, Engineering, Humanities, Music, Natural Sciences and Social Sciences and is home to the Baker Institute for Public Policy. With 3,708 undergraduates and 2,374 graduate students, Rice's undergraduate student-to-faculty ratio is 6-to-1. Its residential college system builds close-knit communities and lifelong friendships, just one reason why Rice has been ranked No. 1 for best quality of life multiple times by the Princeton Review and No. 2 for "best value" among private universities by Kiplinger's Personal Finance. To read "What they're saying about Rice," go to http://tinyurl.com/AboutRice.
Mike Williams | Source: EurekAlert!
Further information: www.rice.edu
Further Reports about: Antenna-on-a-chip > computer engineering > electrical and computer engineering > formation process > high speeds > infrared light > optical fiber > signal processing > SLM > spatial light modulator > speed|scan atlineCT-System
More articles from Power and Electrical Engineering:
New Thermoelectronic Generator
04.12.2013 | American Institute of Physics (AIP)
Defending against electromagnetic attacks
02.12.2013 | Fraunhofer Institute for Technical Trend Analysis INT
International team of scientists develops new feedback method for optimizing the laser pulse shapes used in the control of chemical reactions
In many ways, traditional chemical synthesis is similar to cooking. To alter the final product, you can change the ingredients or their ratio, change the method of mixing ingredients, or change the temperature or pressure of the environment of the ingredients.
Like an accomplished chef, chemists have become very skilled ...
A genetic defect protects mice from infection with influenza viruses
A new study published in the scientific journal PLOS Pathogens points out that mice lacking a protein called Tmprss2 are no longer affected by certain flu viruses.
The discovery was made by researchers from the Helmholtz Centre for Infection Research (HZI) in Braunschweig in collaboration with colleagues from Göttingen and ...
The Light: Global study gets underway with online user survey
Light has a fundamental impact on our sense of well-being and performance. In cooperation with Zumtobel, a supplier of lighting solutions, Fraunhofer IAO has launched a global user survey of lighting quality in offices. The objective is to identify the best lighting conditions for a variety of spaces and lighting ...
Quantum entanglement, a perplexing phenomenon of quantum mechanics that Albert Einstein once referred to as “spooky action at a distance,” could be even spookier than Einstein perceived.
Physicists at the University of Washington and Stony Brook University in New York believe the phenomenon might be intrinsically linked with wormholes, hypothetical features of space-time that in popular science fiction can provide a much-faster-than-light shortcut from one part of the universe to another.
But here’s the catch: One couldn’t actually ...
A star is formed when a large cloud of gas and dust condenses and eventually becomes so dense that it collapses into a ball of gas, where the pressure heats the matter, creating a glowing gas ball – a star is born.
New research from the Niels Bohr Institute, among others, shows that a young, newly formed star in the Milky Way had such an explosive growth, that it was initially about 100 times brighter than it is now. The results are published in the scientific journal, Astrophysical Journal Letters.
The young ...
06.12.2013 | Materials Sciences
06.12.2013 | Life Sciences
06.12.2013 | Life Sciences
05.12.2013 | Event News
04.12.2013 | Event News
12.11.2013 | Event News