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!
Fraunhofer IWKS Starts Project “BReCycle” on Efficient Recycling of Fuel Cells
07.04.2020 | Fraunhofer-Einrichtung für Wertstoffkreisläufe und Ressourcenstrategie IWKS
Synthetic gas instead of fossil energy
07.04.2020 | Empa - Eidgenössische Materialprüfungs- und Forschungsanstalt
Published by Marc Tudela, Laura Becerra-Fajardo, Aracelys García-Moreno, Jesus Minguillon and Antoni Ivorra, in Access, the journal of the Institute of Electrical and Electronics Engineers
The project Electronic AXONs: wireless microstimulators based on electronic rectification of epidermically applied currents (eAXON, 2017-2022), funded by a...
The Belle II experiment has been collecting data from physical measurements for about one year. After several years of rebuilding work, both the SuperKEKB electron–positron accelerator and the Belle II detector have been improved compared with their predecessors in order to achieve a 40-fold higher data rate.
Scientists at 12 institutes in Germany are involved in constructing and operating the detector, developing evaluation algorithms, and analyzing the data.
Electrolytes play a key role in many areas: They are crucial for the storage of energy in our body as well as in batteries. In order to release energy, ions - charged atoms - must move in a liquid such as water. Until now the precise mechanism by which they move through the atoms and molecules of the electrolyte has, however, remained largely unknown. Scientists at the Max Planck Institute for Polymer Research have now shown that the electrical resistance of an electrolyte, which is determined by the motion of ions, can be traced back to microscopic vibrations of these dissolved ions.
In chemistry, common table salt is also known as sodium chloride. If this salt is dissolved in water, sodium and chloride atoms dissolve as positively or...
Drops of water falling on or sliding over surfaces may leave behind traces of electrical charge, causing the drops to charge themselves. Scientists at the Max Planck Institute for Polymer Research (MPI-P) in Mainz have now begun a detailed investigation into this phenomenon that accompanies us in every-day life. They developed a method to quantify the charge generation and additionally created a theoretical model to aid understanding. According to the scientists, the observed effect could be a source of generated power and an important building block for understanding frictional electricity.
Water drops sliding over non-conducting surfaces can be found everywhere in our lives: From the dripping of a coffee machine, to a rinse in the shower, to an...
90 million-year-old forest soil provides unexpected evidence for exceptionally warm climate near the South Pole in the Cretaceous
An international team of researchers led by geoscientists from the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI) have now...
07.04.2020 | Event News
06.04.2020 | Event News
02.04.2020 | Event News
08.04.2020 | Physics and Astronomy
08.04.2020 | Information Technology
08.04.2020 | Medical Engineering