Conventional lenses, made of shaped glass, are limited in how precisely they can redirect beams of incoming light and make them meet at a point. Now, a team led by Zhengtong Liu at the A*STAR Institute of High Performance Computing, Singapore, has proposed a novel approach to ‘superlens’ systems that can surpass this classical limit of focusing light.
The team used numerical modeling to develop the design. Concentrating radiation into a smaller volume in this way enhances the interaction between light and matter, and thus the concept could prove useful in highly sensitive sensors of the future.
Light is a type of wave. Unlike the rise and fall in sea water at a beach, however, a light wave consists of oscillating electric and magnetic fields. The wavelength — the distance a wave travels in one oscillation cycle — imposes a limit on the minimum size to which light can be focused. However, this limit does not apply over small distances that are comparable to the wavelength, which is known as the near-field regime.
The researchers designed a silver nanostructure embedded in glass. Their device combined two separate elements. One component was a nanoantenna — similar to the radio-frequency antennas used to detect television-carrying signals, but reduced in size to match the wavelength of optical radiation. The other component was a superlens made of a thin slab of silver. The purpose of the superlens was to move the light detected by the nanoantenna into an imaging plane. “Using nanoantennas to concentrate light is not a new idea,” says Liu. “But by adding a superlens to translate the concentrated spot of light, we can overcome limitations imposed by the optical properties of the material.”
Liu and co-workers mathematically modeled the optical response of this device to an incoming beam of red light. They then altered the dimensions of the structure to maximize the enhancement in electric field. In this way, they were able to show that a 20-nanometer-thick superlens, separated by 34 nanometers from an antenna made of two silver ellipses, could increase the electric field of light by a factor of 250 (see image).
Confining light into these super intense ‘hot-spots’ could prove a boon for optical detection systems. “Our concept is targeted at biomedical and chemical sensing applications,” explains Liu. “The next step is to seek collaboration opportunities to actually make the sensor and test it in the field.”
The A*STAR-affiliated researchers contributing to this research are from the Institute of High Performance Computing
Liu, Z., Li, E., Shalaev, V. M. & Kildishev, A. V. Near field enhancement in silver nanoantenna-superlens systems. Applied Physics Letters 101, 021109 (2012).
‘Find the Lady’ in the quantum world
17.10.2017 | Rheinische Friedrich-Wilhelms-Universität Bonn
A single photon reveals quantum entanglement of 16 million atoms
16.10.2017 | Université de Genève
Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).
When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...
Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.
How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...
Scientists from the Max Planck Institute of Quantum Optics, using high precision laser spectroscopy of atomic hydrogen, confirm the surprisingly small value of the proton radius determined from muonic hydrogen.
It was one of the breakthroughs of the year 2010: Laser spectroscopy of muonic hydrogen resulted in a value for the proton charge radius that was significantly...
It's possible to produce hydrogen to power fuel cells by extracting the gas from seawater, but the electricity required to do it makes the process costly. UCF...
Mercury, our smallest planetary neighbor, has very little to call an atmosphere, but it does have a strange weather pattern: morning micro-meteor showers.
Recent modeling along with previously published results from NASA's MESSENGER spacecraft -- short for Mercury Surface, Space Environment, Geochemistry and...
17.10.2017 | Event News
10.10.2017 | Event News
10.10.2017 | Event News
17.10.2017 | Event News
17.10.2017 | Physics and Astronomy
16.10.2017 | Physics and Astronomy