Meta-Atoms Alter Light Polarization
CANBERRA, Australia, July 30, 2014 — A new metamaterial that is deformed by light while altering its polarization could become a tool for developing photonic circuits.
A team from Australian National University’s Research School of Physics and Engineering (RSPE) made this new finding while developing metamaterials. These were formed from a pattern of tiny metal shapes called meta-atoms, which were then used to achieve optical rotation.
“Our material can put a twist into light — that is, rotate its polarization — orders of magnitude more strongly than natural materials,” said lead researcher Mingkai Liu, a doctoral candidate at RSPE. “And we can switch the effect on and off directly with light.”
Dr. David Powell, a researcher with Australian National University’s Research School of Physics and Engineering, demonstrates the meta-atoms used to rotate light polarization. Courtesy of Australian National University.
The researchers demonstrated that this effect is “now available in artificial electromagnetic systems, enabled by the advent of magnetoelastic metamaterials” that produce nonlinear effects including self-oscillation, according to the study.
The researchers used a pair of c-shaped meta-atoms, one suspended above the other, to achieve optical rotation. They said that when light shines on the pair of meta-atoms, the top one rotates, making the system asymmetric. Chiral symmetry breaking in the system’s strong stationary response prompts nonlinear polarization change.
“Because light affects the symmetry of our system, you can tune your material’s response simply by shining a light beam on it,” Liu said. “Tunability of a metamaterial is an important step toward building devices based on these artificial materials.”
Such materials could be “another completely new tool in the toolbox for processing light,” according to RSPE researcher Dr. David Powell.
“Thin slices of these materials can replace bulky collections of lenses and mirrors. This miniaturization could lead to the creation of more compact optoelectronic devices, such as a light-based version of the electronic transistor.”
The research was published in Nature Communications (doi: 10.1038/ncomms5441).
For more information, visit www.physics.anu.edu.au.
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