A team of researchers from the RIKEN Center for Emergent Matter Science (CEMS) in Japan has identified unexpected dynamic properties of a type of light wave called evanescent waves. These surprising findings contrast sharply with previous knowledge about light and photons.
The study carried out in the Quantum Condensed Matter Research Group (CEMS, RIKEN, Japan) led by Dr. Franco Nori is published today in the journal Nature Communications.
Energy, momentum, and angular momentum are the main dynamic characteristics of physical objects. It is well known that light propagating as an electromagnetic wave or photon carries momentum along the direction of the wave's propagation, and that this momentum is independent of polarization. In addition, light can carry an intrinsic angular momentum, called spin, that is proportional to the degree of circular polarization (helicity), and aligned with the propagation direction.
The RIKEN team analysed the momentum and spin of evanescent electromagnetic waves – a type of light waves that travel close to the surface of material objects and whose intensity decreases exponentially, rather than varying sinusoidally, from the interface where they were formed.
Surprisingly, the researchers found that evanescent waves carry momentum and spin components that are orthogonal to the direction of wave propagation. Moreover, the transverse spin turns out to be independent of polarization and helicity, while the transverse momentum is proportional to the wave helicity.
"Such extraordinary properties, revealed in very basic objects, offer a unique opportunity to investigate and observe fundamental physical features, which were previously hidden in usual propagating light and were considered impossible," says Dr. Konstantin Bliokh, first author of the study. "In addition to a detailed theoretical analysis, we propose and simulate numerically four novel experiments for the detection of the unusual momentum and spin properties of evanescent waves via their interaction with small probe particles," he adds.
These results add a new chapter to the physics of momentum and spin of classical and quantum fields, and predict a number of novel light-matter interaction effects involving evanescent waves.
For more information please contact:
Mobile phone: +81-(0)80-8895-2136
Extraordinary momentum and spin in evanescent waves
Konstantin Y. Bliokh, Aleksandr Y. Bekshaev, Franco Nori
Nature Communications, 2014 DOI: 10.1038/ncomms4300
RIKEN is Japan's largest research institute for basic and applied research. Over 2500 papers by RIKEN researchers are published every year in leading scientific and technology journals covering a broad spectrum of disciplines including physics, chemistry, biology, engineering, and medical science. RIKEN's research environment and strong emphasis on interdisciplinary collaboration and globalization has earned a worldwide reputation for scientific excellence.
Find us on Twitter at @riken_en
About the Center for Emergent Matter Science
The aim of the research carried out at the Center for Emergent Matter Science (CEMS) is to address humanity's energy problems and contribute to building a sustainable society. Taking a pioneering role in the new field of emergent materials science, scientists at CEMS are developing new, more efficient technologies that will enable us to produce energy without putting a burden on the environment, as well as decrease our energy consumption. They achieve this by combining advanced research in physics, chemistry and electronics in order to produce new technology such as highly efficient energy conversion devices and low-consumption electronics.
Juliette Savin | EurekAlert!
Tracking down the 'missing' carbon from the Martian atmosphere
25.11.2015 | California Institute of Technology
Iowa State astronomers say comet fragments best explanation of mysterious dimming star
25.11.2015 | Iowa State University
The Fraunhofer Institute for Solar Energy Systems ISE has installed 70 photovoltaic modules on the outer façade of one of its lab buildings. The modules were...
Nerve cells cover their high energy demand with glucose and lactate. Scientists of the University of Zurich now provide new support for this. They show for the first time in the intact mouse brain evidence for an exchange of lactate between different brain cells. With this study they were able to confirm a 20-year old hypothesis.
In comparison to other organs, the human brain has the highest energy requirements. The supply of energy for nerve cells and the particular role of lactic acid...
In laser material processing, the simulation of processes has made great strides over the past few years. Today, the software can predict relatively well what will happen on the workpiece. Unfortunately, it is also highly complex and requires a lot of computing time. Thanks to clever simplification, experts from Fraunhofer ILT are now able to offer the first-ever simulation software that calculates processes in real time and also runs on tablet computers and smartphones. The fast software enables users to do without expensive experiments and to find optimum process parameters even more effectively.
Before now, the reliable simulation of laser processes was a job for experts. Armed with sophisticated software packages and after many hours on computer...
Researchers at Heidelberg University have devised a new way to study the phenomenon of magnetism. Using ultracold atoms at near absolute zero, they prepared a...
AWI researchers’ unique 15-year observation series reveals how sensitive marine ecosystems in polar regions are to change
The warming of arctic waters in the wake of climate change is likely to produce radical changes in the marine habitats of the High North. This is indicated by...
25.11.2015 | Event News
17.11.2015 | Event News
21.10.2015 | Event News
25.11.2015 | Agricultural and Forestry Science
25.11.2015 | Earth Sciences
25.11.2015 | Physics and Astronomy