Skip to main content

Nanoantennas : The Future of Communication technology

More than 120 years after the discovery of the electromagnetic character of radiowaves by Heinrich Hertz, wireless data transmission dominates information technology. Higher and higher radio frequencies are applied to transmit more data. Some years ago, scientists found that light waves might also be used for radio transmission. So far, manufacture of the small antennas has required an enormous expenditure. Scientists have now succeeded in specifically and reproducibly manufacturing smallest optical nanoantennas from gold.In 1887, Heinrich Hertz discovered the electromagnetic waves at the former Technical College of Karlsruhe, the predecessor of Universität Karlsruhe (TH). Specific and directed generation of electromagnetic radiation allows for the transmission of information from a place A to a remote location B. The key component in this transmission is a dipole antenna on the transmission side and on the reception side. Today, this technology is applied in many areas of everyday life, for instance, in mobile radio communication or satellite reception of broadcasting programs. Communication between the transmitter and receiver reaches highest efficiency, if the total length of the dipole antennas corresponds to about half of the wavelength of the electromagnetic wave.
Radio transmission by high-frequency electromagnetic light waves in the frequency range of several 100,000 gigahertz (500,000 GHz correspond to yellow light of 600 nm wavelength) requires minute antennas that are not longer than half the wavelength of light, i.e. 350 nm at the maximum (1 nm = 1 millionth of a millimeter). Controlled manufacture of such optical transmission antennas on the nanoscale so far has been very challenging worldwide, because such small structures cannot be produced easily by optical exposure methods for physical reasons, i.e. due to the wave character of the light. To reach the precision required for the manufacture of gold antennas that are smaller than 100 nm, the scientists working in the "Nanoscale Science" DFG-Heisenberg Group at the KIT Light Technology Institute (LTI) used an electron beam process, the so-called electron beam lithography. The results were published recently in the journal Nanotechnology (Nanotechnology 20 (2009) 425203).
These gold antennas act physically like radio antennas. However, the latter are 10 million times as large, they have a length of about 1 m. Hence, the frequency received by nanoantennas is 1 million times higher than radio frequency, i.e. several 100,000 GHz rather than 100 MHz.
These nanoantennas shall transmit information at extremely high data rates, because the high frequency of the waves allows for an extremely rapid modulation of the signal. For the future of wireless data transmission, this means acceleration by a factor of 10,000 at reduced energy consumption. Hence, nanoantennas are considered a major basis of new optical high-speed data networks. The positive side-effect: Light in the range of 1000 to 400 nm is not hazardous for man, animals, and plants.
In the future, nanoantennas from Karlsruhe may not only be used for information transmission, but also as tools for optical microscopy: "With the help of these small nano light emitters, we can study individual biomolecules, which has not been established so far," says Dr. Hans-Jürgen Eisler, who heads the DFG Heisenberg group at the Light Technology Institute. Moreover, the nanoantennas may serve as tools to characterize nanostructures from semiconductors, sensor structures, and integrated circuits. The reason is the efficient capture of light by nanoantennas. Thereafter, they are turned into light emitters and emit light quantums (photons).
The LTI scientists are presently also working on the specific and efficient capture of visible light by means of these antennas and on focusing this light on a few 10 nm, the objective being e.g. the optimization of photovoltaic modules.
Story Source:
Helmholtz Association of German Research Centres. "Smallest Nanoantennas For High-speed Data Networks." ScienceDaily. ScienceDaily, 25 October 2009.
Labels:

Comments

Post a Comment

Popular posts from this blog

Linking hydrogen atom to silicon surface: A new way for greener, smaller and faster electronics

A key step in unlocking the potential for greener, faster, smaller electronic circuitry was taken recently by a group of researchers led by UAlberta physicist Robert Wolkow. The research team found a way to delete and replace out-of-place atoms that had been preventing new revolutionary circuitry designs from working. This unleashes a new kind of silicon chips for used in common electronic products, such as our phones and computers. "For the first time, we can unleash the powerful properties inherent to the atomic scale," explained Wolkow, noting that printing errors on silicon chips are inevitable when working at the atomic scale. "We were making things that were close to perfect but not quite there. Now that we have the ability to make corrections, we can ensure perfect patterns, and that makes the circuits work. It is this new ability to edit at the atom scale that makes all the difference." Think of a typing mistake and the ability to go back and white
Post a Comment
Read more

Nanophotodetectors with nanocavities to improve the performance of optoelectronic devices.

In today's increasingly powerful electronics, tiny materials are a must as manufacturers seek to increase performance without adding bulk. Smaller also is better for optoelectronic devices -- like camera sensors or solar cells -- which collect light and convert it to electrical energy. Think, for example, about reducing the size and weight of a series of solar panels, producing a higher-quality photo in low lighting conditions, or even transmitting data more quickly. However, two major challenges have stood in the way: First, shrinking the size of conventionally used "amorphous" thin-film materials also reduces their quality. And second, when ultrathin materials become too thin, they become almost transparent and actually lose some ability to gather or absorb light. Now, in a nanoscale photodetector that combines a unique fabrication method and light-trapping structures, a team of engineers from the University of Wisconsin-Madison and the University at Buffalo ha
Post a Comment
Read more

Nanoimprinting accelerating the fabrication of nano-optical devices

Combining speed with incredible precision, a team of researchers has developed a way to print a nanoscale imaging probe onto the tip of a glass fiber as thin as a human hair, accelerating the production of the promising new device from several per month to several per day. The high-throughput fabrication technique opens the door for the widespread adoption of this and other nano-optical structures, which squeeze and manipulate light in ways that are unachievable by conventional optics. Nano-optics have the potential to be used for imaging, sensing, and spectroscopy, and could help scientists improve solar cells, design better drugs, and make faster semiconductors. A big obstacle to the technology's commercial use, however, is its time-consuming production process. The new fabrication method, called fiber nanoimprinting, could unplug this bottleneck. It was developed by scientists at the Molecular Foundry, located at the Department of Energy's Lawrence Berkeley Nat
Post a Comment
Read more