The single-layer surface of nanostructures can be incorporated into commercial optical systems, from simple to complex
Today's optical systems -- from smartphone cameras to cutting-edge microscopes -- use technology that hasn't changed much since the mid-1700s.
These are images of a US Air Force resolution target, a microscopic optical resolution test, imaged with (left) and without (right) the metacorrector. The linewidth of the first line in group 7 of the resolution target is 3.91 micrometers. The scale bar is 25 micrometers.
Credit: Capasso Lab/Harvard SEAS
Compound lenses, invented around 1730, correct the chromatic aberrations that cause lenses to focus different wavelengths of light in different spots.
While effective, these multi-material lenses are bulky, expensive, and require precision polishing or molding and very careful optical alignment. Now, a group of researchers at the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS) is asking: Isn't it time for an upgrade?
SEAS researchers have developed a so-called metacorrector, a single-layer surface of nanostructures that can correct chromatic aberrations across the visible spectrum and can be incorporated into commercial optical systems, from simple lenses to high-end microscopes.
The metacorrector eliminated chromatic aberrations in a commercial lens across the entire visible light spectrum. The device also works for the super-complex objectives with as many as 14 conventional lenses, used in high-resolution microscopes.
The research is described in Nano Letters.
"Our metacorrector technology can work in tandem with traditional refractive optical components to improve performance while significantly reducing the complexity and footprint of the system, for a wide range of high-volume applications" said Federico Capasso, the Robert L. Wallace Professor of Applied Physics and Vinton Hayes Senior Research Fellow in Electrical Engineering at SEAS and senior author of the paper.
In previous research, Capasso and his team demonstrated that metasurfaces, arrays of nanopillars spaced less than a wavelength apart, can be used to manipulate the phase, amplitude and polarization of light and enable new, ultra-compact optical devices, including flat lenses. This research uses the same principles to tune and control the effective refractive index of each nanopillar so that all wavelengths are brought by the metacorrector to the same focal point.
"You can imagine light as different packets being delivered at different speeds as it propagates in the nanopillars. We have designed the nanopillars so that all these packets arrive at the focal spot at the same time and with the same temporal width," said Wei Ting Chen, a Research Associate in Applied Physics at SEAS and first author of the paper.
"Using metacorrectors is fundamentally different from conventional methods of aberration correction, such as cascading refractive optical components or using diffractive elements, since it involves nanostructure engineering," said Alexander Zhu, a graduate student at SEAS and co-author of the study. "This means we can go beyond the material limitations of lenses and have much better performances."
Next, the researchers aim to increase efficiency for high-end and miniature optical devices.
Harvard's Office of Technology Development has protected the intellectual property relating to this project and is exploring commercialization opportunities.
This paper was co-authored by Jared Sisler, Yao-Wei Huang, Kerolos M. A. Yousef, Eric Lee, Harvard University and Cheng-Wei Qiu, National University of Singapore.
This research was supported by the Air Force Office of Scientific Research and the Center for Nanoscale Systems (CNS), a member of the National Nanotechnology Coordinated Infrastructure (NNCI), which is supported by the National Science Foundation.
Leah Burrows | EurekAlert!
The holy grail of nanowire production
20.02.2019 | Ecole Polytechnique Fédérale de Lausanne
Combining infrared radiation and air management to reduce energy use
19.02.2019 | Heraeus Noblelight GmbH
Up to now, OLEDs have been used exclusively as a novel lighting technology for use in luminaires and lamps. However, flexible organic technology can offer much more: as an active lighting surface, it can be combined with a wide variety of materials, not just to modify but to revolutionize the functionality and design of countless existing products. To exemplify this, the Fraunhofer FEP together with the company EMDE development of light GmbH will be presenting hybrid flexible OLEDs integrated into textile designs within the EU-funded project PI-SCALE for the first time at LOPEC (March 19-21, 2019 in Munich, Germany) as examples of some of the many possible applications.
The Fraunhofer FEP, a provider of research and development services in the field of organic electronics, has long been involved in the development of...
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...
11.02.2019 | Event News
30.01.2019 | Event News
16.01.2019 | Event News
21.02.2019 | Earth Sciences
21.02.2019 | Trade Fair News
21.02.2019 | Life Sciences