We live in a world made and run by RNA, the equally important sibling of the genetic molecule DNA. In fact, evolutionary biologists hypothesize that RNA existed and self-replicated even before the appearance of DNA and the proteins encoded by it. Fast forward to modern day humans: science h ... more
Broadband achromatic metalens focuses light regardless of polarization
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. 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.
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.
Induced pluripotent stem cells (iPS) have the potential to convert into a wide variety of cell types and tissues. However, the "recipes" for this conversion are often complicated and difficult to implement. Researchers at the Center for Regenerative Therapies Dresden (CRTD) at TU Dresden, H ... more
The composition of suspicious powders that may contain illicit drugs can be analyzed using a quick and simple method called magneto-Archimedes levitation (MagLev), according to a new study published in the journal Angewandte Chemie. A team of scientists at Harvard University, USA, has devel ... more
Researchers from the Harvard John A. Paulson School of Engineering and Applied Sciences have made the world’s smallest radio receiver – built out of an assembly of atomic-scale defects in pink diamonds. This tiny radio — whose building blocks are the size of two atoms — can withstand extrem ... more
- 1Smartphone-powered microchip for at-home medical diagnostic testing developed
- 2Measuring the ‘wettability’ of graphene and other 2D materials
- 3New method revolutionizes cancer diagnosis
- 4analytica 2022: Analytics that benefit consumer and environmental protection
- 5The oat genome unlocks the unique health benefits of oats
- 6New technique shows in detail where drug molecules hit their targets in the body
- 7Bruker and TOFWERK Form Strategic Partnership
- 8analytica 2022: New instruments for personalized medicine
- 9A sharper image for proteins
- 10Nanotechnology enables visualization of RNA structures at near-atomic resolution