Nav: Home

Researchers combine advanced spectroscopy technique with video-rate imaging

February 27, 2020

WASHINGTON -- For the first time, researchers have used an advanced analytical technique known as dual-comb spectroscopy to rapidly acquire extremely detailed hyperspectral images. By acquiring a full spectrum of information for each pixel in a scene with high sensitivity and speed, the new approach could greatly advance a wide range of scientific and industrial applications such as chemical analysis and biomedical sensing.

"Dual-comb spectroscopy has revolutionized optical spectroscopy by providing unmatched spectral resolution and accuracy as well as short acquisition times without moving parts," said research team leader Pedro Martín-Mateos from Universidad Carlos III de Madrid, in Spain. "Our new direct hyperspectral dual-comb imaging approach will make it possible to expand most of the point-detection capabilities of current dual-comb systems to create a spectral image of an entire scene."

Dual-comb spectroscopy uses two optical sources, known as optical frequency combs, that emit a spectrum of colors - or frequencies - that are perfectly spaced like the teeth on a comb. As reported in Optica, The Optical Society's journal for high impact research, this is the first time that a dual-comb spectrum has been directly detected using a video camera.

"We demonstrate spectral interrogation of a 2D object in just one second, more than three orders of magnitude faster than previous demonstrations," said Martín-Mateos. "This fast acquisition time enables dual-comb hyperspectral imaging of fast or dynamic processes, which wasn't possible before."

Although the work was performed using near-infrared wavelengths, the researchers say that the concept can be easily transferred to a variety of spectral regions, widening the number of possible applications.

In particular, expanding the approach to the terahertz and millimeter wave spectral regions would open many new opportunities for nondestructive testing and product inspection in the food, agricultural and pharmaceutical industries. In the mid-infrared and the near-infrared regions it could also enhance the performance of chemical imaging, 3D mapping and surface topography technologies.

Video-rate detection

Dual-comb spectrometers work by interfering light from two closely matched optical frequency combs. This mixing process generates a signal known as an interferogram at rates that are typically in the tens of megahertz (million times per second), too fast to capture with even the fastest high-speed video cameras.

"We stretched the interferograms generated by our system up to a second to make it possible to detect the dual-comb interference signal using a video camera," explained Martín-Mateos. "This allows the spectral analysis of an entire scene, instead of just a point."

To do this the researchers built a system based on a very simple electro-optic dual-comb source made mostly of optical fiber components. The use of two acousto-optic modulators let them offset the optical combs by an arbitrarily low frequency, to create ultra-slow interferograms.

The researchers used the new method to acquire hyperspectral images of ammonia gas escaping from a bottle. They achieved an optical resolution of 1 GHz (0.0033 cm-1) at video rates of 25 frames per second, with each frame containing 327,680 individual spectral measurements. According to the researchers, the resolution they achieved allows easy distinction between different gases and is 100 times better than current commercial equipment.

"This enables us, for example, to easily identify and distinguish between different gases. The resolution demonstrated in this first experimental demonstration is two orders of magnitude better than that of current commercial equipment.

"Simplicity is one of the main strengths of the system," said Martín-Mateos. "It worked flawlessly and could be implemented in any optics laboratory."

The work is part of a larger project funded by the ATTRACT initiative (Horizon 2020), which aims to develop a fast hyperspectral imaging system that uses the terahertz region of the electromagnetic spectrum for inspection, quality control and classification of agricultural and food products. The researchers are now working to develop a terahertz dual-comb source to demonstrate the method in this spectral region.
-end-
Paper: P. Martín-Mateos, F. U. Khan, O. E. Bonilla Manrique, "Direct hyperspectral dual-comb imaging," Optica, 7, 3, 199-202 (2020).
DOI: https://doi.org/10.1364/OPTICA.382887

About Optica

Optica is an open-access, journal dedicated to the rapid dissemination of high-impact peer-reviewed research across the entire spectrum of optics and photonics. Published monthly by The Optical Society (OSA), Optica provides a forum for pioneering research to be swiftly accessed by the international community, whether that research is theoretical or experimental, fundamental or applied. Optica maintains a distinguished editorial board of more than 60 associate editors from around the world and is overseen by Editor-in-Chief Prem Kumar, Northwestern University, USA. For more information, visit Optica.

About The Optical Society

Founded in 1916, The Optical Society (OSA) is the leading professional organization for scientists, engineers, students and business leaders who fuel discoveries, shape real-life applications and accelerate achievements in the science of light. Through world-renowned publications, meetings and membership initiatives, OSA provides quality research, inspired interactions and dedicated resources for its extensive global network of optics and photonics experts. For more information, visit osa.org.

Media Contacts:

Aaron Cohen

(301) 633-6773
aaroncohenpr@gmail.com

mediarelations@osa.org

The Optical Society

Related Agricultural Articles:

Agricultural pickers in US to see unsafely hot workdays double by 2050
Temperature increases by 2050 and 2100 in U.S. counties where crops are grown will double, then triple the number of unsafe workdays.
Digital agriculture paves the road to agricultural sustainability
In a study published in Nature Sustainability, researchers outline how to develop a more sustainable land management system through data collection and stakeholder buy-in.
Significant potential demonstrated by digital agricultural advice
2019 Economics Nobel Laureate co-publishes paper demonstrating the potential for digital agricultural advice to 'sustainably' raise 'agricultural productivity' at low cost for 2 billion smallholder farming families.
Sustaining roads with grape and agricultural waste
The US spends $5 billion a year to repair damages to road infrastructure from winter snow and ice control operations and the use of traditional deicers.
New report says accelerating global agricultural productivity growth is critical
The 2019 Global Agricultural Productivity Report, released today by Virginia Tech's College of Agriculture and Life Sciences, shows agricultural productivity growth -- increasing output of crops and livestock with existing or fewer inputs -- is growing globally at an average annual rate of 1.63%.
The benefits of updating agricultural drainage infrastructure
The massive underground infrastructure that allows farmers to cultivate crops on much of the world's most productive land has outlived its design life and should be updated, according to a new study.
The next agricultural revolution is here
By using modern gene-editing technologies to learn key insights about past agricultural revolutions, two plant scientists are suggesting that the next agricultural revolution could be at hand.
Stop the exploitation of migrant agricultural workers across Italy
Writing in The BMJ today, Dr Claudia Marotta and colleagues say more than 1,500 agricultural workers have died as a result of their work over the past six years, while others have been killed by the so-called 'Caporali' who are modern slave masters.
New mechanism of action found for agricultural pesticide fludioxonil
A fungicide commonly used by the agricultural industry to protect grains, fruit and vegetables from mold damage seems to kill fungi by a previously uncharacterized mechanism that delivers a metabolic shock to cells, new research at the University of Wisconsin-Madison finds.
Strontium isotope maps are disturbed by agricultural lime
Strontium isotopes are frequently used in archaeological studies to establish the provenance and migration history of prehistoric people and artifacts.
More Agricultural News and Agricultural Current Events

Trending Science News

Current Coronavirus (COVID-19) News

Top Science Podcasts

We have hand picked the top science podcasts of 2020.
Now Playing: TED Radio Hour

Listen Again: Meditations on Loneliness
Original broadcast date: April 24, 2020. We're a social species now living in isolation. But loneliness was a problem well before this era of social distancing. This hour, TED speakers explore how we can live and make peace with loneliness. Guests on the show include author and illustrator Jonny Sun, psychologist Susan Pinker, architect Grace Kim, and writer Suleika Jaouad.
Now Playing: Science for the People

#565 The Great Wide Indoors
We're all spending a bit more time indoors this summer than we probably figured. But did you ever stop to think about why the places we live and work as designed the way they are? And how they could be designed better? We're talking with Emily Anthes about her new book "The Great Indoors: The Surprising Science of how Buildings Shape our Behavior, Health and Happiness".
Now Playing: Radiolab

The Third. A TED Talk.
Jad gives a TED talk about his life as a journalist and how Radiolab has evolved over the years. Here's how TED described it:How do you end a story? Host of Radiolab Jad Abumrad tells how his search for an answer led him home to the mountains of Tennessee, where he met an unexpected teacher: Dolly Parton.Jad Nicholas Abumrad is a Lebanese-American radio host, composer and producer. He is the founder of the syndicated public radio program Radiolab, which is broadcast on over 600 radio stations nationwide and is downloaded more than 120 million times a year as a podcast. He also created More Perfect, a podcast that tells the stories behind the Supreme Court's most famous decisions. And most recently, Dolly Parton's America, a nine-episode podcast exploring the life and times of the iconic country music star. Abumrad has received three Peabody Awards and was named a MacArthur Fellow in 2011.