Close Menu
  • News
  • Medical
  • Technology
  • Nanomaterials
  • Research
  • Blog
    • Nasiol.com
  • Contact
    • Tech7685@gmail.com
What's Hot

Photoresponsive cages show promise for tunable supramolecular electronics

May 24, 2025

Targeted nanoparticles show promise for more effective antifungal treatments

May 23, 2025

Dynamic visualizations expose how domain walls shift in ferroelectrics

May 23, 2025
Facebook X (Twitter) Instagram
Nanotech – Nanomaterials | Medical | Research | News Stories Updated Daily Nanotech – Nanomaterials | Medical | Research | News Stories Updated Daily
  • News
  • Medical
  • Technology
  • Nanomaterials
  • Research
  • Blog
    • Nasiol.com
  • Contact
    • Tech7685@gmail.com
Facebook X (Twitter) Instagram
Nanotech – Nanomaterials | Medical | Research | News Stories Updated Daily Nanotech – Nanomaterials | Medical | Research | News Stories Updated Daily
Home»News»Harvard Scientists Control “Points of Darkness” for Remote Sensing and Covert Detection Applications
News

Harvard Scientists Control “Points of Darkness” for Remote Sensing and Covert Detection Applications

August 11, 2023No Comments5 Mins Read
Facebook Twitter Pinterest Telegram LinkedIn Tumblr WhatsApp Email
Harvard Scientists Control “Points of Darkness” for Remote Sensing and Covert Detection Applications
Share
Facebook Twitter LinkedIn Pinterest Telegram Email

By Kat J. McAlpine, Harvard John A. Paulson School of Engineering and Applied Sciences
July 5, 2023

Harvard researchers have developed techniques to control “points of darkness” in light using metasurfaces, opening up new possibilities in fields like remote sensing, precision measurement, and covert detection. The team created precise dark spots that can capture atoms or act as measurement points for imaging, and developed resilient “polarization singularities,” stable dark spots in polarized optical fields. This is a scanning electron microscope image of the metasurface that generated the point singularities. Credit: Harvard University

Two studies report new methods for using metasurfaces to create and control dark areas called “optical singularities.”

Optical devices and materials allow scientists and engineers to harness light for research and real-world applications, like sensing and microscopy. Federico Capasso’s group at the Harvard John A. Paulson School of Engineering Applied Sciences (SEAS) has dedicated years to inventing more powerful and sophisticated optical methods and tools. Now, his team has developed new techniques to exert control over points of darkness, rather than light, using metasurfaces.

“Dark regions in electromagnetic fields, or optical singularities, have traditionally posed a challenge due to their complex structures and the difficulty in shaping and sculpting them. These singularities, however, carry the potential for groundbreaking applications in fields such as remote sensing and precision measurement,” said Capasso, the Robert L. Wallace Professor of Applied Physics and Vinton Hayes Senior Research Fellow in Electrical Engineering at SEAS and senior corresponding author on two new papers describing the work.

Experimental Intensity Profiles

Experimental intensity profiles, with the point singularities labeled. Credit: Harvard University

In 2011, Capasso’s lab introduced metasurfaces, or sub-wavelength-spaced arrays of nanostructures. In 2016, they used metasurfaces to build high-performance metalenses – flat optical lenses comprising nanopillars that they fabricated using semiconductor lithography techniques – which unlocked a new strategy to focus light using extremely lightweight devices.

The newest studies from the Capasso group – published in Nature Communications and Science Advances – report how metasurface technology can harness not just light, but also darkness.

“Both of these studies introduce new classes of optical singularities – regions of designed darkness – using powerful but intuitive algorithms to inform the fabrication of metasurfaces,” said Soon Wei Daniel Lim, co-first author of the paper in Nature Communications with Joon-Suh Park.

In that study, Lim and collaborators designed and fabricated an optical device containing metasurfaces of titanium dioxide nanopillars that can control light to create an array of optical singularities.

To control exactly where these points of darkness appear, Lim used a computer algorithm to help him reverse engineer the design of the metasurface.

“I told the computer: Here’s what I want to achieve in terms of dark spots, tell me what shape and diameter the nanopillars should be on this metasurface to make this happen,” he said.

As light travels through the metasurface and lens, it generates a prescribed array of dark spots.

“These dark spots are exciting because they could be used as optical traps to capture atoms,” Lim said. “It’s possible this could be used to simplify the optical architecture used in atomic physics labs, replacing today’s conventional equipment – instruments that take up 30 feet of space on a lab table – with compact, lightweight optical devices.”

Dark spots aren’t just handy for trapping atoms. They can also be useful as highly precise reference positions for imaging.

“Points of darkness are much smaller than points of light,” Lim said. “As part of an imaging system, that makes them effective points of measurement to accurately discriminate between two different positions within a sample.”

In their Science Advances paper, the Capasso group described a new class of optical singularities: extremely stable points of darkness in a polarized optical field, known as polarization singularities.

“We’ve designed points of darkness that can withstand a wide range of perturbations — they are topologically protected,” said Christina Spaegele, first author of the paper. “This robustness opens the way to optical devices with high reliability and durability in various applications.”

Previous research achieved some polarization singularities, but the conditions for maintaining that perfect spot of darkness were extremely fragile, making them easily destroyed by stray light or other environmental conditions.

“By shining light through a specially-designed metasurface and focusing lens, we can produce an unwavering polarization singularity surrounded entirely by points of light – essentially creating a dark spot inside a sphere of brightness,” Spaegele said.

The technique is so robust that even introducing a defect to the metasurface doesn’t destroy the dark spot, but simply shifts its position.

“This degree of control could be especially useful for imaging samples in ‘hostile’ environments, where vibrations, pressure, temperature, and stray light would typically interfere with imaging behavior,” Spaegele said.

The team says these new developments in optical singularities have implications for remote sensing and covert detection.

“Points of darkness could be used to mask out bright sources while imaging a scene, allowing us to see faint objects that are otherwise overshadowed,” Capasso said. “Objects or detectors placed at these dark positions will also not give away their position by scattering light, allowing them to be ‘hidden’ without affecting the surrounding light.”

References:

“Point singularity array with metasurfaces” by Soon Wei Daniel Lim, Joon-Suh Park, Dmitry Kazakov, Christina M. Spägele, Ahmed H. Dorrah, Maryna L. Meretska and Federico Capasso, 5 June 2023, Nature Communications.
DOI: 10.1038/s41467-023-39072-6

“Topologically protected optical polarization singularities in four-dimensional space” by Christina M. Spaegele, Michele Tamagnone, Soon Wei Daniel Lim, Marcus Ossiander, Maryna L. Meretska and Federico Capasso, 16 June 2023, Science.
DOI: 10.1126/sciadv.adh0369

Harvard’s Office of Technology Development has protected the intellectual property arising from these studies and is exploring commercialization opportunities.

Additional authors who contributed to these papers include Dmitry Kazakov, Ahmed H. Dorrah, Maryna L. Meterska, Michele Tamagnone, and Marcus Ossiander.

This research was supported by the Air Force Office of Scientific Research and the European Research Council.


Source link

See also  An Introduction to Fluorescent Silica Nanobeads
Applications control Covert Darkness detection Harvard Points Remote Scientists Sensing
Share. Facebook Twitter Pinterest LinkedIn Tumblr Email

Related Posts

Photoresponsive cages show promise for tunable supramolecular electronics

May 24, 2025

Targeted nanoparticles show promise for more effective antifungal treatments

May 23, 2025

Dynamic visualizations expose how domain walls shift in ferroelectrics

May 23, 2025

Nanoscale spectroscopy detects vibrational signals from molecules in confined gaps

May 22, 2025

Controlling contaminants inside nanopores holds promise for desalination, carbon dioxide storage and porous catalysts

May 22, 2025

Modified glass fiber microstructure could illuminate blood vessel health from within

May 21, 2025

Comments are closed.

Top Articles
News

What Is a Semiconductor and How Does It Work?

News

Controlling sound waves with Klein tunneling improves acoustic signal filtration

News

New strategies enhance stability of metal nanoparticles in green hydrogen production

Editors Picks

Photoresponsive cages show promise for tunable supramolecular electronics

May 24, 2025

Targeted nanoparticles show promise for more effective antifungal treatments

May 23, 2025

Dynamic visualizations expose how domain walls shift in ferroelectrics

May 23, 2025

Special contact lenses let you see infrared light – even in the dark

May 22, 2025
About Us
About Us

Your go-to source for the latest nanotechnology breakthroughs. Explore innovations, applications, and implications shaping the future at the molecular level. Stay informed, embrace the nano-revolution.

We're accepting new partnerships right now.

Facebook X (Twitter) Instagram Pinterest
Our Picks

Quantum interference could lead to smaller, faster, and more energy-efficient transistors

March 31, 2024

The Global Race in Nanotechnology: A Comparative Analysis of National Strategies for Investors

May 10, 2024

Amorphous nanosheets created using hard-to-synthesize metal oxides and oxyhydroxides

October 29, 2024

Subscribe to Updates

Get the latest creative Nano Tech news from Elnano.com

© 2025 Elnano.com - All rights reserved.
  • Contact
  • Privacy Policy
  • Terms & Conditions

Type above and press Enter to search. Press Esc to cancel.

Cleantalk Pixel