A landmark experiment on wave interference from the early 1800s is revisited using gold nanoparticles
In the eighteenth century, scientists faced a conundrum: is light a wave or a particle? One of strongest pieces of evidence to support the ‘wave view’ — the landmark double-slit experiment — was reported in 1804 by the scientist Thomas Young. Young passed coherent light through two closely spaced slits and observed a set of interference fringes, a result that occurs with wave phenomena like sound or water. This observation became the basis for the modern wave theory of light.
Example of the energy flow and optical vortices found around closely spaced gold nanoparticles. The effects resemble the field lines seen in Young’s slit experiments.
Copyright : 2014 A*STAR Data Storage Institute
Two hundred years later, Arseniy Kuznetsov and co-workers from the A*STAR Data Storage Institute, together with collaborators in Australia, Singapore, the United Kingdom and Russia, have performed an experiment analogous to Young’s experiments but using nanoscale objects (1). The team studied the light scattering in the visible and near-infrared wavelength regions from a cluster of two or three closely spaced gold plasmonic nanoparticles. They observed interference and resonance effects that resemble those seen in Young’s experiments.
In particular, while studying a trimer system consisting of three discrete metallic nanodisks of about 145 nanometers in diameter and 60 nanometers thick, the team found evidence for the presence of near-field, subwavelength-sized optical vortices and the circulation of electromagnetic energy (see image). This finding is very similar to what occurs to the energy flow pattern in a Young-type experiment performed with three slits.
One of the key issues in nanoplasmonics is the interaction between metallic nanoparticles at the nanoscale. “Even if the separation between two or multiple non-periodically arranged nanoparticles is of the order of wavelength, their interaction can be strong enough to change their scattering and absorption properties,” notes Kuznetsov. “This can be explained by the peculiarities of the Poynting vector (energy) flow around the nanoparticles and formation of optical vortices, which produce a pattern of field lines similar to Young’s classic experiment.”
The team’s findings, says Kuznetsov, not only expand our fundamental understanding of how light interacts with nanoclusters of metallic particles, but have both theoretical and practical applications. “They may also prove useful for applications such as improved solar cells and plasmonic biosensors.” However, their most remarkable application, he suggests, may be in the emerging area of nanoantennas.
In the future, the team is aiming to study the resonant properties and interactions of nanoparticles made from nonmetallic materials. In particular, they plan to investigate high-refractive index dielectric materials such as silicon, which, unlike metallic particles, do not suffer from high optical losses.
The A*STAR-affiliated researchers contributing to this research are from the Data Storage Institute
Rahmani, M., Miroshnichenko, A. E., Lei, D. Y., Luk’yanchuk, B., Tribelsky, M. I. et al. Beyond the hybridization effects in plasmonic nanoclusters: Diffraction-induced enhanced absorption and scattering. Small 10, 576–583 (2013).
Streamlining accelerated computing for industry
24.08.2016 | DOE/Oak Ridge National Laboratory
Lehigh engineer discovers a high-speed nano-avalanche
24.08.2016 | Lehigh University
Scientists and engineers striving to create the next machine-age marvel--whether it be a more aerodynamic rocket, a faster race car, or a higher-efficiency jet...
Waveguides are widely used for filtering, confining, guiding, coupling or splitting beams of visible light. However, creating waveguides that could do the same for X-rays has posed tremendous challenges in fabrication, so they are still only in an early stage of development.
In the latest issue of Acta Crystallographica Section A: Foundations and Advances , Sarah Hoffmann-Urlaub and Tim Salditt report the fabrication and testing of...
Electrochemists at TU Graz have managed to use monocrystalline semiconductor silicon as an active storage electrode in lithium batteries. This enables an integrated power supply to be made for microchips with a rechargeable battery.
Small electrical gadgets, such as mobile phones, tablets or notebooks, are indispensable accompaniments of everyday life. Integrated circuits in the interiors...
Recent findings indicating the possible discovery of a previously unknown subatomic particle may be evidence of a fifth fundamental force of nature, according...
A nanocrystalline material that rapidly makes white light out of blue light has been developed by KAUST researchers.
25.08.2016 | Event News
24.08.2016 | Event News
12.08.2016 | Event News
26.08.2016 | Health and Medicine
26.08.2016 | Earth Sciences
26.08.2016 | Life Sciences