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!
Appreciating the classical elegance of time crystals
20.09.2019 | ETH Zurich Department of Physics
'Nanochains' could increase battery capacity, cut charging time
20.09.2019 | Purdue University
For applications such as light-emitting diodes or solar cells, organic materials are nowadays in the focus of research. These organic molecules could be a promising alternative to currently used semiconductors such as silicon or germanium and are used in OLED displays. A major problem is that in many organic semiconductors the flow of electricity is hampered by microscopic defects. Scientists around Dr. Gert-Jan Wetzelaer and Dr. Denis Andrienko of the Max-Planck-Institute for Polymer Research have now investigated how organic semiconductors can be designed such that the electric conduction is not influenced by these defects.
The basic principle of the first light bulb, invented by Thomas Edison in the 19th century, was quite simple: Electrons – negatively charged particles – flow...
How long the battery of your phone or computer lasts depends on how many lithium ions can be stored in the battery's negative electrode material. If the battery runs out of these ions, it can't generate an electrical current to run a device and ultimately fails.
Materials with a higher lithium ion storage capacity are either too heavy or the wrong shape to replace graphite, the electrode material currently used in...
To process information, photons must interact. However, these tiny packets of light want nothing to do with each other, each passing by without altering the...
Researchers from the Department of Atomically Resolved Dynamics of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg, the University of Hamburg and the European Molecular Biology Laboratory (EMBL) outstation in the city have developed a new method to watch biomolecules at work. This method dramatically simplifies starting enzymatic reactions by mixing a cocktail of small amounts of liquids with protein crystals. Determination of the protein structures at different times after mixing can be assembled into a time-lapse sequence that shows the molecular foundations of biology.
The functions of biomolecules are determined by their motions and structural changes. Yet it is a formidable challenge to understand these dynamic motions.
At the International Symposium on Automotive Lighting 2019 (ISAL) in Darmstadt from September 23 to 25, 2019, the Fraunhofer Institute for Organic Electronics, Electron Beam and Plasma Technology FEP, a provider of research and development services in the field of organic electronics, will present OLED light strips of any length with additional functionalities for the first time at booth no. 37.
Almost everyone is familiar with light strips for interior design. LED strips are available by the metre in DIY stores around the corner and are just as often...
19.09.2019 | Event News
10.09.2019 | Event News
04.09.2019 | Event News
24.09.2019 | Life Sciences
24.09.2019 | Life Sciences
24.09.2019 | Materials Sciences