New design doubles the efficiency of the metalens
We live in a polarized world. No, we aren't talking about politics -- we're talking about light. Much of the light we see and use is partially polarized, meaning its electric field vibrates in specific directions.
These newly designed nano-structures on the surface of a metalens can focus light regardless of its polarization, doubling the efficiency of the lens.
Credit: Capasso Lab/Harvard SEAS
Lenses designed to work across a range of applications, from phone cameras to microscopes and sensors, need to be able to focus light regardless of its polarization.
Researchers believed that symmetric nanostructures such as circular pillars were essential building blocks to develop photonic devices that are not sensitive to polarization.
Now, researchers from the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS) have developed a polarization-insensitive metalens comprised of non-symmetric nanofins that can achromatically focus light across the visible spectrum without aberrations.
This flat lens could be used for everything from virtual or augmented reality headsets to microscopy, lithography, sensors, and displays.
"By making this lens polarization insensitive, we have doubled the efficiency of the metalens from previous iterations," said Wei Ting Chen, a research associate at SEAS and first author of the paper. "This is the first paper that demonstrates both achromatic and polarization insensitive focusing in the visible spectrum."
The research was led by Federico Capasso, the Robert L. Wallace Professor of Applied Physics and Vinton Hayes Senior Research Fellow in Electrical Engineering at SEAS, and published in Nature Communications.
In previous research, Capasso, Chen and their team demonstrated that arrays of titanium dioxide nanofins could equally focus wavelengths of light and eliminate chromatic aberration, but those lenses could only focus a circularly polarized light.
"This meant we were essentially discarding half of the incident light which does not possess the right polarization," said Alexander Zhu, co-author of the study and graduate student at SEAS.
In this latest design, the researchers changed the layout of the nanofins, positioning each pillar so that it is either parallel or perpendicular to its neighbor.
"This new design gives us a lot of freedom to tune the geometrical parameters of the metalens, which allows us to better achieve achromatic focusing across the entire visible range," said Chen.
"Next we aim to maximize efficiency and make much larger-size achromatic metalenses to bring them into everyday life for a wide range of applications," said Capasso
Harvard's Office of Technology Development has protected the intellectual property relating to this project and is exploring commercialization opportunities.
This research was co-authored by Jared Sisler, and Zameer Bharwani. It was supported by the Air Force Office of Scientific Research and the Defense Advanced Research Projects Agency.
Leah Burrows | EurekAlert!
Gravitational waves will settle cosmic conundrum
15.02.2019 | Simons Foundation
Spintronics by 'straintronics'
15.02.2019 | Helmholtz-Zentrum Berlin für Materialien und Energie
For the first time, an international team of scientists based in Regensburg, Germany, has recorded the orbitals of single molecules in different charge states in a novel type of microscopy. The research findings are published under the title “Mapping orbital changes upon electron transfer with tunneling microscopy on insulators” in the prestigious journal “Nature”.
The building blocks of matter surrounding us are atoms and molecules. The properties of that matter, however, are often not set by these building blocks...
Scientists at the University of Konstanz identify fierce competition between the human immune system and bacterial pathogens
Cell biologists from the University of Konstanz shed light on a recent evolutionary process in the human immune system and publish their findings in the...
Laser physicists have taken snapshots of carbon molecules C₆₀ showing how they transform in intense infrared light
When carbon molecules C₆₀ are exposed to an intense infrared light, they change their ball-like structure to a more elongated version. This has now been...
The so-called Abelian sandpile model has been studied by scientists for more than 30 years to better understand a physical phenomenon called self-organized...
Physicists from the University of Basel have developed a new method to examine the elasticity and binding properties of DNA molecules on a surface at extremely low temperatures. With a combination of cryo-force spectroscopy and computer simulations, they were able to show that DNA molecules behave like a chain of small coil springs. The researchers reported their findings in Nature Communications.
DNA is not only a popular research topic because it contains the blueprint for life – it can also be used to produce tiny components for technical applications.
11.02.2019 | Event News
30.01.2019 | Event News
16.01.2019 | Event News
15.02.2019 | Physics and Astronomy
15.02.2019 | Physics and Astronomy
15.02.2019 | Life Sciences