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!
Lights, camera, action... the super-fast world of droplet dynamics
26.02.2020 | University of Leeds
Turbomachine expander offers efficient, safe strategy for heating, cooling
25.02.2020 | Purdue University
Researchers at the University of Bayreuth have discovered an unusual material: When cooled down to two degrees Celsius, its crystal structure and electronic properties change abruptly and significantly. In this new state, the distances between iron atoms can be tailored with the help of light beams. This opens up intriguing possibilities for application in the field of information technology. The scientists have presented their discovery in the journal "Angewandte Chemie - International Edition". The new findings are the result of close cooperation with partnering facilities in Augsburg, Dresden, Hamburg, and Moscow.
The material is an unusual form of iron oxide with the formula Fe₅O₆. The researchers produced it at a pressure of 15 gigapascals in a high-pressure laboratory...
Study by Mainz physicists indicates that the next generation of neutrino experiments may well find the answer to one of the most pressing issues in neutrino physics
Among the most exciting challenges in modern physics is the identification of the neutrino mass ordering. Physicists from the Cluster of Excellence PRISMA+ at...
Fraunhofer researchers are investigating the potential of microimplants to stimulate nerve cells and treat chronic conditions like asthma, diabetes, or Parkinson’s disease. Find out what makes this form of treatment so appealing and which challenges the researchers still have to master.
A study by the Robert Koch Institute has found that one in four women will suffer from weak bladders at some point in their lives. Treatments of this condition...
The operational speed of semiconductors in various electronic and optoelectronic devices is limited to several gigahertz (a billion oscillations per second). This constrains the upper limit of the operational speed of computing. Now researchers from the Max Planck Institute for the Structure and Dynamics of Matter in Hamburg, Germany, and the Indian Institute of Technology in Bombay have explained how these processes can be sped up through the use of light waves and defected solid materials.
Light waves perform several hundred trillion oscillations per second. Hence, it is natural to envision employing light oscillations to drive the electronic...
Most natural and artificial surfaces are rough: metals and even glasses that appear smooth to the naked eye can look like jagged mountain ranges under the microscope. There is currently no uniform theory about the origin of this roughness despite it being observed on all scales, from the atomic to the tectonic. Scientists suspect that the rough surface is formed by irreversible plastic deformation that occurs in many processes of mechanical machining of components such as milling.
Prof. Dr. Lars Pastewka from the Simulation group at the Department of Microsystems Engineering at the University of Freiburg and his team have simulated such...
12.02.2020 | Event News
16.01.2020 | Event News
15.01.2020 | Event News
28.02.2020 | Materials Sciences
28.02.2020 | Life Sciences
28.02.2020 | Architecture and Construction