Today's optical system – from smartphones to advanced microscopes – uses technology that has not changed much since the mid-18th…
Today’s optical system – from smartphones to advanced microscopes – uses technology that has not changed much since the mid-18th century. Composite lenses, invented around 1730, correct chromatic abnormalities that cause lenses to focus different wavelengths of light in different spots. While effective, these multi-media lenses are bulky, expensive and require precision polishing or casting and very accurate optical alignment. Now a group of researchers at Harvard John A. Paulson’s School of Engineering and Applied Sciences (SEAS) asks: Is not it time for an upgrade?
SEAS researchers have developed a so-called metacorrector layered surface of nanostructures that can correct chromatic aberrations over the visible spectrum and can be incorporated into commercial optical systems, from simple lenses to advanced microscopes. Metacorrector eliminated chromatic aberrations in a commercial lens across visible light spectrum. The device also works for the supercomplex targets with as many as 1
4 conventional lenses, used in high resolution microscopes.
The research is described in Nano Letters .
“Our meta correction technology can work in tandem with traditional refractory optical components to improve performance while reducing system complexity and footprint considerably for a wide range of high volume applications,” said Federico Capasso, Robert L. Wallace Professor of Applied Physics and Vinton Hayes Senior Research Fellow in Electrical Engineering at SEAS and senior author of the magazine.
In previous research, Capasso and his team demonstrated that metasurfaces, nanopartar assemblies less than one wavelength apart, can be used to manipulate phase, amplitude and polarization of light, enabling new, ultra compact optical devices, including flat lenses. This research uses the same principles to match and control the effective refractive index of each nanopillar so that all wavelengths are brought by the metacorrector to the same point of contact.
“You can imagine light because different packages are delivered at different speeds as it propagates in the nanopartners. We have designed the nanopilliers so that all these packages reach the focal point at the same time and with the same temporal width,” said Wei Ting Chen, research assistant in applied physics at SEAS and the first author of paper.
“Using metacoractors differs fundamentally from conventional correction correction methods, such as cascade-breaking optical components or diffraction element utilization, as it involves nanostructure technology,” said Alexander Zhu, a doctoral student at SEAS and co-author of the study. “This means we can go beyond the limitations of the lens and have much better performance.”
The researchers aim to increase the efficiency of advanced and miniature optical devices.
Harvard’s Technical Development Agency has protected intellectual property related to this pro kt and investigates commercialization opportunities.
Material provided by Harvard John A. Paulson Technical University . Original written by Leah Burrows. Note! Content can be edited for style and length.