A single layer of metallic nanostructures has been designed, fabricated and tested by a team of Penn State electrical engineers that can provide exceptional capabilities for manipulating light. This engineered surface, which consists of a periodic array of strongly coupled nanorod resonators, could improve systems that perform optical characterization in scientific devices, such as ellipsometers; sensing, such as biosensing of proteins; or satellite communications.
“We have designed and fabricated a waveplate that can transform the polarization state of light,” said Zhi Hao Jiang, a postdoctoral fellow in electrical engineering and lead author of a recent paper in Scientific Reports explaining their invention. “Polarization is one of the most fundamental properties of light. For instance, if we transform linearly polarized light into circularly polarized light, this could be useful in optical communication and biosensing.”
Zhi Hao Jiang, Penn State
On the left, circularly polarized light is converted to a linearly polarized wave upon reflection in a metasurface-based quarter-wave plate. On the right, a top-view FESEM image of the fabricated nanostructure showing the nanorod array. (Bottom scale bar - 400 nm. Top scale bar – 100 nm)
Optical waveplates with broadband polarization conversion over a wide field of view are highly sought after. Conventional waveplates, made from multilayer stacks of materials such as quartz, have difficulty achieving both broadband and wide-angle conversion.
Thin waveplates have been demonstrated, but their efficiency was low, with an average power efficiency of less than 50 percent. The team’s nanofabricated waveplates achieved measured polarization conversion rates higher than 92 percent over more than an octave bandwidth with a wide field-of-view of around 40 degrees.
“In this paper, we demonstrated with simulation and experiment both quarter-waveplate and half-waveplate metasurfaces, which are thin artificial surfaces that operate both in the visible spectrum as well as in the near infrared,” said Jeremy Bossard, a postdoc who is a member of the team but not an author on the paper. “It also has a wide field of view, which means that if you illuminate the surface from a wide range of angles, it would still give the same reflective performance.”
As a component in an optical setup, the nanostructured waveplate offers a thinner form factor and reduced weight for space applications, a wider field of view, which can reduce the number of optical components in a system, and can achieve very wide broadband functionality in the visible to near infrared wavelength range. This represents a new state-of-the-art for optical meta-surface based devices and will enable other types of ultrathin highly efficient optical components, the authors said.
The waveplate was designed by Jiang using global optimization methods. It was fabricated in the Penn State Nanofabrication Laboratory by doctoral student Lan Lin, and characterized by doctoral student Ding Ma. Co-authors include Seokho Yun, a former postdoctoral scholar in the Penn State Electrical Engineering Department, Douglas H. Werner, John L. and Genevieve H. McCain Chair Professor of Electrical Engineering, Zhiwen Liu,professor of electrical engineering, and Theresa Mayer, Distinguished Professor of Electrical Engineering. The paper is titled “Broadband and Wide field-of-view Plasmonic Metasurface-enabled Waveplates.”
This work was supported by the National Science Foundation through Penn State’s Center for Nanoscale Science.
Douglas Werner firstname.lastname@example.org
Zhiwen Liu email@example.com
Theresa Mayer firstname.lastname@example.org
Walter Mills | newswise
In borophene, boundaries are no barrier
17.07.2018 | Rice University
Research finds new molecular structures in boron-based nanoclusters
13.07.2018 | Brown University
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.
Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...
13.07.2018 | Event News
12.07.2018 | Event News
03.07.2018 | Event News
18.07.2018 | Life Sciences
18.07.2018 | Life Sciences
18.07.2018 | Information Technology