Flat optical device has applications in augmented and virtual reality, ultra-high resolution microscopy, holography
Researchers at the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS) have developed a flat optical component that is simultaneously a metalens, a microscope objective that can resolve details smaller than a wavelength of light, and an optical vortex and hologram generator. Each functionality is controlled by a different wavelength of light.
"The breakthrough of this new flat optical device is that it can radically change its function based on the wavelength of light it reflects," said Federico Capasso, the Robert Wallace Professor of Applied Physics at SEAS and senior author of the research. "By tying functionality to wavelength, we have opened up a whole range of new possibilities for metasurfaces."
The research was published in Nano Letters.
"In this research, we decoupled functions at different wavelengths," said Zhujun Shi, first author of the paper and graduate student at SEAS. "Compared to previous flat optical devices, this device has an extra degree of freedom that you can tune at different wavelengths. For example, at one color, this lens behaves like a traditional metalens but at another wavelength, it generates a vortex beam."
The Harvard Office of Technology Development has protected the intellectual property relating to this project and is exploring commercialization opportunities.
The lens builds on previous technology developed in the Capasso Lab, which used different polarized light to change the function of a lens. But since there are only two forms of circularly polarized light -- clockwise or counterclockwise -- the researchers could embed only two different functions in the metasurface.
"By controlling the device function with wavelength, rather than polarization that is bound to two states, we have dramatically increased the information capacity of the lens," said Mohammadreza Khorasaninejad, co-first author of the paper and former postdoctoral fellow in the Capasso Lab. "With this technology, we demonstrated an achromatic metalens in blue, green, yellow and red wavelengths, two beam generators, and a full-color hologram."
While this is not the first lens to tie function to wavelength, it is the most efficient. Previous wavelength-dependent metalenses encoded different functions in different areas of the surface; for example, red light would be focused in one quadrant and blue light in another.
With this technology, Shi and the rest of the team engineered the individual nanoscale optical elements to embed functionality at the local level, across the entire lens.
"By encoding everything locally, in a single layer, we improved efficiency from 8 percent demonstrated in previous wavelength-dependent metasurfaces to more than 30 percent," said Yao-Wei Huang, co-first author of the paper and postdoctoral fellow at SEAS.
Next, the team aims to improve that efficiency even further and develop a transmitting, rather than a reflective lens.
This research was co-authored by Charles Roques-Carmes, Alexander Y. Zhu, Wei Ting Chen, Vyshakh Sanjeev, ZhaoWei Ding, Michele Tamagnone, Kundan Chaudhary, Robert C. Devlin, and Cheng-Wei Qiu. It was supported in part by the Air Force Office of Scientific Research.
Leah Burrows | EurekAlert!
A cavity leads to a strong interaction between light and matter
22.10.2019 | Universität Basel
A new stable form of plutonium discovered at the ESRF
21.10.2019 | European Synchrotron Radiation Facility
Researchers have succeeded in creating an efficient quantum-mechanical light-matter interface using a microscopic cavity. Within this cavity, a single photon is emitted and absorbed up to 10 times by an artificial atom. This opens up new prospects for quantum technology, report physicists at the University of Basel and Ruhr-University Bochum in the journal Nature.
Quantum physics describes photons as light particles. Achieving an interaction between a single photon and a single atom is a huge challenge due to the tiny...
A very special kind of light is emitted by tungsten diselenide layers. The reason for this has been unclear. Now an explanation has been found at TU Wien (Vienna)
It is an exotic phenomenon that nobody was able to explain for years: when energy is supplied to a thin layer of the material tungsten diselenide, it begins to...
Researchers at Ludwig-Maximilians-Universitaet (LMU) in Munich have explored the initial consequences of the interaction of light with molecules on the surface of nanoscopic aerosols.
The nanocosmos is constantly in motion. All natural processes are ultimately determined by the interplay between radiation and matter. Light strikes particles...
Particles that are mere nanometers in size are at the forefront of scientific research today. They come in many different shapes: rods, spheres, cubes, vesicles, S-shaped worms and even donut-like rings. What makes them worthy of scientific study is that, being so tiny, they exhibit quantum mechanical properties not possible with larger objects.
Researchers at the Center for Nanoscale Materials (CNM), a U.S. Department of Energy (DOE) Office of Science User Facility located at DOE's Argonne National...
A new research project at the TH Mittelhessen focusses on the development of a novel light weight design concept for leisure boats and yachts. Professor Stephan Marzi from the THM Institute of Mechanics and Materials collaborates with Krake Catamarane, which is a shipyard located in Apolda, Thuringia.
The project is set up in an international cooperation with Professor Anders Biel from Karlstad University in Sweden and the Swedish company Lamera from...
02.10.2019 | Event News
02.10.2019 | Event News
19.09.2019 | Event News
22.10.2019 | Life Sciences
22.10.2019 | Life Sciences
22.10.2019 | Power and Electrical Engineering