Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Dual frequency comb generated on a single chip using a single laser

05.03.2018

Columbia Engineers are the first to miniaturize dual-frequency combs by putting two frequency comb generators on a single millimeter-sized silicon-based chip; could lead to low-cost, portable sensing, and spectroscopy in the field in real-time.

In a new paper published today in Science Advances, researchers under the direction of Columbia Engineering Professors Michal Lipson and Alexander Gaeta (Applied Physics and Applied Mathematics) have miniaturized dual-frequency combs by putting two frequency comb generators on a single millimeter-sized chip.


A compact, integrated, silicon-based chip used to generate dual combs for extremely fast molecular spectroscopy.

Credit: A. Dutt, A. Mohanty, E. Shim, G. Patwardhan/Columbia Engineering

"This is the first time a dual comb has been generated on a single chip using a single laser," says Lipson, Higgins Professor of Electrical Engineering.

A frequency comb is a special kind of light beam with many different frequencies, or "colors," all spaced from each other in an extremely precise way. When this many-color light is sent through a chemical specimen, some colors are absorbed by the specimen's molecules. By looking at which colors have been absorbed, one can uniquely identify the molecules in the specimen with high precision. This technique, known as frequency-comb spectroscopy, enables molecular fingerprinting and can be used to detect toxic chemicals in industrial areas, to implement occupational safety controls, or to monitor the environment.

"Dual-comb spectroscopy is this technique put on steroids," says Avik Dutt, former student in Lipson's group (now a postdoctoral scholar at Stanford) and lead author of the paper. "By mixing two frequency combs instead of a single comb, we can increase the speed at which measurement are made by thousandfolds or more."

The work also demonstrated the broadest frequency span of any on-chip dual comb?i.e., the difference between the colors on the low-frequency end and the high-frequency end is the largest. This span enables a larger variety of chemicals to be detected with the same device, and also makes it easier to uniquely identify the molecules: the broader the range of colors in the comb, the broader the diversity of molecules that can see the colors.

Conventional dual-comb spectrometers, which have been introduced over the last decade, are bulky tabletop instruments, and not portable due to their size, cost, and complexity. In contrast, the Columbia Engineering chip-scale dual comb can easily be carried around and used for sensing and spectroscopy in field environments in real time.

"There is now a path for trying to integrate the entire device into a phone or a wearable device," says Gaeta, Rickey Professor of Applied Physics and of Materials Science.

The researchers miniaturized the dual comb by putting both frequency comb generators on a single millimeter-sized chip. They also used a single laser to generate both the combs, rather than the two lasers used in conventional dual combs, which reduced the experimental complexity and removed the need for complicated electronics. To produce miniscule rings?tens of micrometers in diameter?that guide and enhance light with ultralow loss, the team used silicon nitride, a glass-like material they have perfected specifically for this purpose. By combining the silicon nitride with platinum heaters, they were able to very finely tune the rings and make them work in tandem with the single input laser.

"Silicon nitride is a widely used material in the silicon-based semiconductor industry that builds computer/smartphone chips," Lipson notes. "So, by leveraging the capabilities of this mature industry, we can foresee reliable fabrication of these dual comb chips on a massive scale at a low cost."

Using this dual comb, Lipson's and Gaeta's groups demonstrated real-time spectroscopy of the chemical dichloromethane at very high speeds, over a broad frequency range. A widely used organic solvent, dichloromethane is abundant in industrial areas as well as in wetland emissions. The chemical is carcinogenic, and its high volatility poses acute inhalation hazards. Columbia Engineering's compact, chip-scale dual comb spectrometer was able to measure a broad spectrum of dichloromethane in just 20 microseconds (there are 1,000,000 microseconds in one second), a task that would have taken at least several seconds with conventional spectrometers.

As opposed to most spectrometers, which focus on gas detection, this new, miniaturized spectrometer is especially suited for liquids and solids, which have broader absorption features than gases?the range of frequencies they absorb is more spread out. "That's what our device is so good at generating," Gaeta explains. "Our very broad dual combs have a moderate spacing between the successive lines of the frequency comb, as compared to gas spectrometers which can get away with a less broad dual comb but need a fine spacing between the lines of the comb."

The team is working on broadening the frequency span of the dual combs even further, and on increasing the resolution of the spectrometer by tuning the lines of the comb. In a paper published last November in Optics Letters, Gaeta's and Lipson's groups demonstrated some steps towards showing an increased resolution.

"One could also envision integrating the input laser into the chip for further miniaturizing the system, paving the way for commercializing this technology in the future," says Dutt.

###

About the Study

The study is titled "On-chip dual comb source for spectroscopy."

Authors are: Avik Dutt, Chaitanya Joshi, and Xingchen Ji (Columbia Engineering and Cornell University); Jaime Cardenas (Columbia Engineering, now at University of Rochester); Kevin Luke (Cornell University); Yoshitomo Okawachi, Alexander L. Gaeta, and Michal Lipson (Columbia Engineering).

The study was funded by the Defense Advanced Research Projects Agency (N66001-16-1-4052, W31P4Q-15-1-0015) and the Air Force Office of Scientific Research (FA9550-15-1-0303). The chips were fabricated at the Cornell Nanoscale Facility.

The authors declare that they have no competing interests.

LINKS:

Paper: http://advances.sciencemag.org/content/4/3/e1701858

DOI: 10.1126/sciadv.1701858

http://engineering.columbia.edu/

http://www.ee.columbia.edu/michal-lipson

http://apam.columbia.edu/alexander-l-gaeta

https://www.osapublishing.org/ol/abstract.cfm?uri=ol-42-21-4442

Columbia Engineering

Columbia Engineering, based in New York City, is one of the top engineering schools in the U.S. and one of the oldest in the nation. Also known as The Fu Foundation School of Engineering and Applied Science, the School expands knowledge and advances technology through the pioneering research of its more than 200 faculty, while educating undergraduate and graduate students in a collaborative environment to become leaders informed by a firm foundation in engineering. The School's faculty are at the center of the University's cross-disciplinary research, contributing to the Data Science Institute, Earth Institute, Zuckerman Mind Brain Behavior Institute, Precision Medicine Initiative, and the Columbia Nano Initiative. Guided by its strategic vision, "Columbia Engineering for Humanity," the School aims to translate ideas into innovations that foster a sustainable, healthy, secure, connected, and creative humanity.

Holly Evarts | EurekAlert!

More articles from Physics and Astronomy:

nachricht Appreciating the classical elegance of time crystals
20.09.2019 | ETH Zurich Department of Physics

nachricht 'Nanochains' could increase battery capacity, cut charging time
20.09.2019 | Purdue University

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: 'Nanochains' could increase battery capacity, cut charging time

How long the battery of your phone or computer lasts depends on how many lithium ions can be stored in the battery's negative electrode material. If the battery runs out of these ions, it can't generate an electrical current to run a device and ultimately fails.

Materials with a higher lithium ion storage capacity are either too heavy or the wrong shape to replace graphite, the electrode material currently used in...

Im Focus: Stevens team closes in on 'holy grail' of room temperature quantum computing chips

Photons interact on chip-based system with unprecedented efficiency

To process information, photons must interact. However, these tiny packets of light want nothing to do with each other, each passing by without altering the...

Im Focus: Happy hour for time-resolved crystallography

Researchers from the Department of Atomically Resolved Dynamics of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg, the University of Hamburg and the European Molecular Biology Laboratory (EMBL) outstation in the city have developed a new method to watch biomolecules at work. This method dramatically simplifies starting enzymatic reactions by mixing a cocktail of small amounts of liquids with protein crystals. Determination of the protein structures at different times after mixing can be assembled into a time-lapse sequence that shows the molecular foundations of biology.

The functions of biomolecules are determined by their motions and structural changes. Yet it is a formidable challenge to understand these dynamic motions.

Im Focus: Modular OLED light strips

At the International Symposium on Automotive Lighting 2019 (ISAL) in Darmstadt from September 23 to 25, 2019, the Fraunhofer Institute for Organic Electronics, Electron Beam and Plasma Technology FEP, a provider of research and development services in the field of organic electronics, will present OLED light strips of any length with additional functionalities for the first time at booth no. 37.

Almost everyone is familiar with light strips for interior design. LED strips are available by the metre in DIY stores around the corner and are just as often...

Im Focus: Tomorrow´s coolants of choice

Scientists assess the potential of magnetic-cooling materials

Later during this century, around 2060, a paradigm shift in global energy consumption is expected: we will spend more energy for cooling than for heating....

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Optical Technologies: International Symposium „Future Optics“ in Hannover

19.09.2019 | Event News

Society 5.0: putting humans at the heart of digitalisation

10.09.2019 | Event News

Interspeech 2019 conference: Alexa and Siri in Graz

04.09.2019 | Event News

 
Latest News

Quality control in immune communication: Chaperones detect immature signaling molecules in the immune system

20.09.2019 | Life Sciences

Moderately Common Plants Show Highest Relative Losses

20.09.2019 | Life Sciences

The Fluid Fingerprint of Hurricanes

20.09.2019 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>