Optical communications, or photonics, technology has failed to match the miniaturization of electronic components, mainly because of fundamental laws of classical optics. The smallest photonic devices are limited to sizes of at least a micrometer. Researchers from the A*STAR Institute of Microelectronics (IME) in Singapore have now realized a device design that beats such size restrictions and can be easily integrated into a silicon chip1.
Using so-called ‘plasmonic techniques’, the researchers, led by Shiyang Zhu at the IME, demonstrated optical resonator structures, which allow a beam of light to circulate in a closed path, that can be used as on-off switches for light. The device is based on plasmonic effects that guide the light along the surface of the metal. “The performance of our devices is comparable to the best reported results for related plasmonic resonators,” says Zhu.
Conventional optical instruments, such as lenses, modify light as it passes through them. Plasmonic structures, however, act more like antennae that amplify light as it moves along their surface. Plasmonic features are typically created using metals such as gold or silver. However, integrating these noble metals with silicon chips is not only expensive, but also requires techniques that are incompatible with established silicon processing techniques.
As a workaround, Zhu and co-workers used copper to generate the desired plasmonic effects. Copper is widely used as electronic wires in silicon computer chips, and it has an established track record in the computer industry. The researchers built their plasmonic resonator devices from two copper structures that guide light along them - a long wire adjacent to a circle. The smallest width of the copper circuit is only about 180 nanometers, which is much smaller than conventional light guides.
The closeness of the wire and the circle is critical for efficient device operation. When light of a specific wavelength, which is determined by the dimensions of the circle, passes through the wire, some of it can leak into the circle where it becomes trapped. Light can only pass through the structure if it does not match the resonance wavelength of the circle.
The wavelength at which this resonance occurs is very sensitive to parameters such as temperature. In the future, this sensitivity in the circuits could be harnessed for use as switches that control how light passes through the wire, says Zhu. “The next step is to design and demonstrate active plasmonic devices, such as thermo-optic switchers and high-speed electro-optic modulators.”
The A*STAR-affiliated researchers contributing to this research are from the Institute of Microelectronics
Zhu, S., Lo, G. Q. & Kwong, D. L. Performance of ultracompact copper-capped silicon hybrid plasmonic waveguide-ring resonators at telecom wavelengths. Optics Express 20, 15232–15246 (2012)
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