optics

CU Boulder leads $5.9 million marine carbon dioxide removal monitoring effort

Anonymous — Tue, 14 Nov 2023 07:00:00 +0000

CU Boulder leads $5.9 million marine carbon dioxide removal monitoring effort Anonymous (not verified) Tue, 11/14/2023 - 00:00

Charles Ferrer

While the closest ocean — the Pacific — may be nearly 900 miles from campus, CU Boulder is advancing marine carbon dioxide removal (mCDR) techniques to cut harmful greenhouse gasses by providing new methods for monitoring verification and reporting.

Juliet Gopinath, the Alfred T. and Betty E. Look Endowed Professor in the Department of Electrical, Computer and Energy Engineering, is spearheading this major endeavor to combat climate change as part of a federal effort.

She is leading the three-year, $5.9 million project called “SLEUTH: Spectroscopy of Oceanic Liquid Environments Using Towed Optical Sensor Heads” through the U.S. Department of Energy’s recent announcement for 11 projects in supporting novel efforts to measure, report and validate mCDR and identify cost-effective and energy efficient carbon removal solutions.

“If we want to limit the amount that the planet is warming, we have to be very aggressive about monitoring what is in the ocean and looking at mCDR,” said Gopinath.

She pointed to the recent impacts of climate change in Colorado as personal motivation to work on this project.

“Many of us have seen the effects of climate change in the Marshall Fire and more extremes here in the West,” she said. “This project’s mission is ultimately trying to slow climate change.”

The SLEUTH team is developing a system of optical underwater sensors utilizing broadband lasers and Raman spectroscopy to sense and measure dissolved carbon compounds. These sensor heads will be towed on a cable containing optical fibers attached to a Wave Glider, an autonomous boat that runs by harvesting wave and solar energy.

Collaboration from Sea to Shining Sea

Gopinath is collaborating with Greg Rieker, an associate professor in the Paul M. Rady Mechanical Engineering Department.

“This project brings us one step closer to having sharks with lasers on their head,” said Rieker. “But in all honesty, monitoring dissolved carbon is an incredibly important enabler for carbon markets. It’s a complex problem,” said Rieker, “and Juliet brought together a diverse team to tackle it.”

The team brings a variety of multidisciplinary expertise together from five subcontractors — including businesses, laboratories and universities — that will play a critical role in creating these new underwater sensors aimed at quantifying the effectiveness of mCDR techniques.

Gopinath’s fascination with the ocean will come in handy quite soon, and she will be joined by researchers from both U.S. coasts.

“I happen to love the ocean after living in Boston for 20 years,” she said. “The stars aligned to put together this incredible team.”

SLEUTH is collaborating with Kristen Davis, an oceanographer from the University of California Irvine, and Ryan Smith, an underwater roboticist from Florida International University, whose oceanographic experience will be pivotal for this marine endeavor.

For phase one of the project, they plan on conducting tests to detect carbon using the optical sensors in Biscayne Bay near Miami, Fla. This will culminate in a field experience in open deep waters in Hawaii, where Liquid Robotics is located.

Other SLEUTH partners include: Liquid Robotics, a marine robotics company that manufactures the Wave Glider uncrewed surface vehicle, tasked with transporting these sensor technologies; Cambridge Consultants, a global product development and technology consultancy, will create the self-cleaning fluidics sampling cell capable of withstanding ocean pressures at depth; and OFS, a global provider of optical fibers, which will create the fibers to be towed underwater.

Making a Difference

mCDR techniques take advantage of the ocean’s natural carbon capture and storage processes. They have the potential to remove hundreds of millions of tons of harmful carbon dioxide emissions per year, according to the DOE.

The mCDR takes place across large surfaces or volumes of the ocean over comparatively long periods of time, and this federal effort is capable of scaling cost-effective techniques in measuring mCDR toward meeting clean energy and climate goals.

If measuring carbon compounds is successful underwater, demonstrating these technologies can allow researchers and federal agencies to evaluate strengths of these mCDR techniques.

“I am really interested in being able to make a difference in people’s lives, and this technology could do that,” said Gopinath.

Selection for award negotiations is not a commitment by DOE to issue an award or provide funding. Before funding is issued, DOE and the applicants will undergo a negotiation process, and DOE may cancel negotiations and rescind the selection for any reason during that time.

As part of a major federal endeavor to combat climate change, CU Boulder is advancing marine carbon dioxide removal techniques to cut harmful greenhouse gasses by providing new methods for monitoring verification and reporting.

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Musgrave earns Department of Defense NDSEG fellowship

Anonymous — Wed, 12 Jul 2023 18:02:37 +0000

Musgrave earns Department of Defense NDSEG fellowship Anonymous (not verified) Wed, 07/12/2023 - 12:02

Charles Ferrer

Jonathan Musgrave has earned a 2023 National Defense Science and Engineering Graduate (NDSEG) Fellowship for his promising research in laser physics and nonlinear photonics.

Musgrave, a second year photonics and quantum engineering doctoral student, received the prestigious Department of Defense (DoD) fellowship. The fellowship was established to recognize and support science and engineering PhD students in disciplines of military importance.

The award includes a three-year monthly stipend and coverage of tuition, fees and insurance, along with a $5,000 travel budget for professional development through the Air Force Office of Scientific Research.

This year, the DoD awarded 165 individuals at 68 institutions nationwide, including nine from CU Boulder's College of Engineering and Applied Science.

We sat down with Musgrave to share some thoughts on his research and how it could impact optics in the future.

Where did your academic journey begin and how did you choose to study optics?

I knew I wanted to study physics and engineering and learn how things work. When I first studied physics at the University of Rochester it was unknown to me they were really well known for optical sciences. And that set me on this journey that optics was what interested me the most in physics, especially after doing research experiences during my undergraduate. My experience back home in Hawaii studying adaptive optics at the Institute for Astronomy was my main inspiration to pursue research.

What is your specific area of research?

Our lab fundamentally focuses on the intersection of light and matter and how they interact. This field of research has been vital for major technological developments, such as frequency combs. What I mostly focus on is developing novel laser systems. We leverage these lasers and high-intensity physics to study novel phenomena in non-linear systems. There’s a whole world of new opportunities that are yet to be worked on and I really think there's a lot of promise in this field, especially in mulitmode nonlinear photonics.

What do you hope your laser optics research will inform?

Lasers are used in almost every industry. We hope to solve matters in biomedical imaging, communication bandwidth and remote sensing. For instance, we are engineering a method to measure extremely low level fluorescence signals at a high sampling rate. We hope this will help in creating a non-invasive diagnostic tool for neurodegenerative disease. We focus on making the physics work and ultimately working with others to make these systems deployable.

What project are you focusing on for the fellowship?

Scaling optical lasers to have greater power with high volume light cavities. In the field of photonics there is interest in studying the self-organization of high dimensional systems. By increasing the study of optics beyond just the temporal domain into the spatial domain a new breadth of technologies may be open to us. What we've proposed for this fellowship is to study some of these novel multimodal nonlinear phenomena that exist in space and time that are showing a lot of promise in our field right now.

What does earning this fellowship mean to you and what most excites you about it?

Grad school is very much a marathon and to be recognized by the community by receiving this fellowship was reaffirming to the work I have completed thus far. I'm very fortunate. In a year or two I’m hoping to visit a few labs and my dream would be to visit a few European institutions like the EPFL in Switzerland who are leaders in the field of optics.

What has been one of the most fulfilling experiences for you here at CU Boulder?

I mentored an undergraduate interested in research opportunities and laser science. It’s quite daunting as an undergraduate getting your foot in the door, but the Undergraduate Research Opportunities Program is a great way for students to have a grad student mentor who’s been in their shoes. You not only teach them how to read journal articles, how to use Google Scholar, but also work on a research poster together. These are important skills that are transferable no matter what area of research you do.

What's next for you after completing your PhD?

I always think of shooting for academia like shooting for the moon. I would love to be in a faculty position. As a TA, I love seeing the ‘aha’ moments when collaborating with my mentors and seeing undergraduate students that I’ve mentored come into their own. I love the field of optics and being in academia you get to define what you want to do and who you want to be. That freedom is invaluable to me.

What are some hobbies that keep you grounded while not researching?

I'm an avid mountaineer, whether it’s hiking, running or skiing off them. There’s a lot of parallels between being in academia and being an athlete. You get to see yourself improve physically and it parallels your academic journey where you see yourself improve intellectually. A lot of engineers are type A and love data. In cardio and endurance sports you get to watch yourself trend upward and learn every way to be more aerodynamic and improve. I love it.

Is there anything else that you want our readers to know?

Our lab is open to having new students and we are always looking for students who are interested in learning more about optics and want to get their foot in the door in research and writing papers. If you're willing to just be curious about how things work and put in the time to learn, that's all you need.

PhD student Jonathan Musgrave earned a 2023 National Defense Science and Engineering Graduate Fellowship for his promising research in laser physics and nonlinear photonics.

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Cross-disciplinary collaboration leads to advancement in ‘liquid lenses’

Anonymous — Wed, 17 May 2023 13:38:43 +0000

Cross-disciplinary collaboration leads to advancement in ‘liquid lenses’ Anonymous (not verified) Wed, 05/17/2023 - 07:38

Miscles in the CU MEMS lab

Eduardo Miscles is a third-year PhD student in mechanical engineering who was recently first author on a paper that presents a significant advancement in the field of adaptive optics.

Miscles’ study, titled "Axisymmetrical resonance modes in an electrowetting optical lens" and published in the journal Applied Physics Letters, was a collaboration between Victor Bright’s CU MEMS lab in mechanical engineering and Juliet Gopinath’s lab in electrical, computer and energy engineering. It sheds light on the impact of low-frequency mechanical vibrations on electrowetting-based devices and promotes their application in diverse fields such as microscopy, LIDAR and machine vision imaging systems.

Can you tell us a little about this paper and its impact?

Our collaboration focuses on electrowetting-based adaptive optics, which allows us to manipulate liquid interfaces using a capacitive effect for precise optical control. We are interested in fabricating and characterizing these devices and then utilizing them for applications in diverse fields such as microscopy, LIDAR, wavefront correction and machine vision imaging systems.

The first thought I had when I met with Bright and Gopinath to learn about the research was, “Liquid lenses? Wouldn’t the waves on the liquid interface destroy your lens?” So I was excited to explore the influence of low-frequency mechanical vibration on these devices and show that my first instinct was wrong — a well-designed liquid lens is extremely robust to external vibrations.

In the paper, a simple theoretical model is used to accurately predict resonance modes induced on the liquid interface and numerical simulations confirm the model. Through experimentation, we successfully validated the resonance frequencies by electrically inducing interfacial surface waves and find that the observed resonance frequencies aligned remarkably well with the roots of the zero-order Bessel functions of the first kind, confirming the robustness of the theoretical framework.

Notably, my first instinct may not have been totally incorrect. In the paper, we demonstrated that external axial vibrations significantly impact electrowetting lenses when the liquids used have vastly different densities. Conversely, when using density-matched liquids, the lenses showed exceptional resilience to vibrations. We were even able to use the electrowetting lens to mitigate power loss through a shaking optical system! This opens doors to novel applications in the field, including live animal imaging, LIDAR technology, and machine vision imaging systems, where precise and stable imaging is vital, but the application is inherently in a vibratory environment.

What is the next step for this project?

I think the study's findings hold immense promise for diverse applications, such as interface shape control, active optical system vibration compensation, and interfacial wave cancelation for innovative liquid combinations. By showing the robustness of electrowetting optics, this research sets the stage for future investigations in the field. With this knowledge, we can now develop strategies to mitigate the impact of vibrations and create more robust imaging systems for various applications. The paper serves as a foundation for future endeavors aimed at refining electrowetting optics for real-world deployment.

What’s your favorite part about the research you do and/or the lab you work in?

My favorite part of my research is the collaboration itself. Between Dr. Bright and Dr. Gopinath, I have two advisors with varying but extremely complimentary expertise. Aside from the principal investigators, the lab members I work with daily continue this trend, having vastly different backgrounds ranging from chemistry and physics to electrical and mechanical engineering.

I am excited to continue my work on electrowetting based adaptive optics and using them in novel and exciting optical systems.

PhD student's study, published in the journal Applied Physics Letters, sheds light on the impact of low-frequency mechanical vibrations on electrowetting-based devices and promotes their application in diverse fields.

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New laser technique has applications in gas sensing and photonic radio frequency sources

Anonymous — Mon, 05 Dec 2022 18:05:48 +0000

New laser technique has applications in gas sensing and photonic radio frequency sources Anonymous (not verified) Mon, 12/05/2022 - 11:05

Thariq Shanavas is a fourth-year physics PhD student who works in the Gopinath Lab in electrical, computer and energy engineering. He was recently first author on a paper in the journal APL Photonics that reported the first observation of cascaded forward stimulated Brillouin scattering in a microresonator platform.

We asked Shanavas to share some more on this new laser technique, as well as his experiences as a graduate student at CU Boulder.

Can you tell us a little about this paper and its impact?

Our work focuses on making inexpensive, high-quality lasers using newly discovered materials. Lasers are used in medical imaging, optical disc drives, laser printers, barcode scanners, DNA sequencing instruments, fiber-optic communication, semiconducting chip manufacturing, laser surgery, and skin treatments among a plethora of other applications. Our research group aims to explore novel applications of lasers by building laser light sources in regimes where few options are currently available.

The color of light is characterized by a parameter called its wavelength. For example, red light has a wavelength of about 700 nanometers (nm), green light about 500 nanometers, and blue light about 450 nanometers. Colors invisible to the human eye have a wavelength either less than 400 nanometers or greater than 800 nanometers.

Among other cool stuff, our group is interested in building lasers in the infrared region, which is light with wavelength between 800 nanometers and 20,000 nanometers. The infrared region is often called the “chemical fingerprint” region because many chemicals absorb light at very specific wavelengths in this range.

For example, water absorbs light at 2662 nm, 2734 nm, and 6269 nm. So if the light from a distant star bounces off a planet and the reflected light is missing these wavelengths, it is likely that there is water in the planet’s atmosphere! Similarly, we could shine a laser through an unknown chemical sample and deduce its composition by looking at the wavelengths of the light that is absorbed. This technique is called spectroscopy and is widely used to identify and characterize chemicals.

For many applications of lasers, including spectroscopy, we require that the laser emit light at a very specific wavelength, with minimal spread around the target wavelength. This “spread” is called the linewidth of a laser and is one of the parameters that characterize the quality of a laser.

One way to reduce this spread is to bounce light off of phonons in a material. Without going into too much detail, phonons are the quanta of mechanical vibrations the same way photons are the quanta of light. This process is called Brillouin scattering. Our work demonstrates a new way to enhance this process in an extremely compact volume that is less than a hundredth of an inch across. We have achieved this by using an optical “resonator” in the shape of a microscopic sphere, which allows the light to circulate along its edge and build up in a closed path.

While we demonstrated a laser that emits light at wavelength 1550 nm, our technique can be used to make a laser at higher wavelengths too! Besides the uses in spectroscopy we talked about earlier, we expect our work to advance the field of integrated photonics, such as sensors-on-a-chip for measuring the concentration of ammonia in the atmosphere. In our paper, we also highlight some ways our research could be used to make/improve electronic frequency synthesizers, which are used in modern devices like radio receivers and GPS systems.

What is the next step for this research project?

Our demonstration was the first of its kind. Therefore, we used the simplest design of a “resonator” that allowed us to demonstrate the type of Brillouin scattering we were interested in – a sphere resonator. For future work, we plan on using our in-house designed microscopic wedge resonators with configurable angles, diameters, and thicknesses. We believe it would improve the brightness of our laser by at least 100 times, unlocking more new and exciting applications!

What’s your favorite part about the research you do and/or the lab you work in?

I like the collaborative nature of our work! Over the course of this project, I got to work with material scientists, physicists, and electrical engineers and drew inspiration from their unique expertise.

I also found the open-ended nature of our research very exciting. When I started this work, I had a very different vision for what the end product would look like. But along the way, I ran into several limitations of what is allowed by the laws of nature. My expectations and vision evolved with my understanding of laser physics, until almost we were done with the final product.

PhD student Thariq Shanavas shares more on the project and his experiences as an interdisciplinary graduate student.

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Gopinath group advances quantum sensing with a new model in optical fibers

Anonymous — Wed, 02 Nov 2022 14:17:13 +0000

Gopinath group advances quantum sensing with a new model in optical fibers Anonymous (not verified) Wed, 11/02/2022 - 08:17

Research into quantum engineering may provide a number of significant advancements in sensor technology, but optical loss and signal noise have – until recently – held these applications back.

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CU getting new new electron beam lithography system for quantum engineering, nanofabrication

Anonymous — Wed, 07 Sep 2022 19:43:09 +0000

CU getting new new electron beam lithography system for quantum engineering, nanofabrication Anonymous (not verified) Wed, 09/07/2022 - 13:43

A state-of-the-art instrument coming soon to CU Boulder will improve research around quantum engineering and may eventually prove to be a game-changer for interdisciplinary materials and device research in the Rocky Mountain region.

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As U.S. ramps up semiconductor production, engineers are probing new tiny electronics

Anonymous — Wed, 31 Aug 2022 13:56:40 +0000

As U.S. ramps up semiconductor production, engineers are probing new tiny electronics Anonymous (not verified) Wed, 08/31/2022 - 07:56

In CU Boulder's COSINC lab, researchers like Won Park use state-of-the art tools to design incredibly small electronic devices—some features measuring just 10 nanometers in size, or less than a millionth of an inch.

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Researchers make strides in commercializing simplified dual-comb spectroscopy

Anonymous — Tue, 30 Aug 2022 13:57:25 +0000

Researchers make strides in commercializing simplified dual-comb spectroscopy Anonymous (not verified) Tue, 08/30/2022 - 07:57

Emily Adams

Huang (left) and a graduate student discuss a project in their lab.

It is sometimes said that science is about truth, while engineering is about compromise.

With one laser project in his lab in the Department of Electrical, Computer and Energy Engineering, Shu-Wei Huang and his team are working on a compromise in order to find new applications for a powerful new technology and make it easier to commercialize.

As they looked at the innovative and extremely precise dual-comb spectroscopy being honed by mechanical engineering Associate Professor Greg Rieker and others, Huang’s team saw an opportunity to expand its applications.

“We've been trying to see whether we can compromise the performance a little bit to greatly simplify the architecture,” Huang said. “The application that we are especially interested in is the biomedical application because in biomedical applications, you don't need the same resolution you need to do something like methane detection.”

The result is the counter-propagating all-normal dispersion (CANDi) fiber laser, which won Bowen Li, a postdoctoral researcher in Huang’s lab, a prestigious award from Optica in 2021.

The key has been a redesigned laser cavity that allows for light to travel both clockwise and counterclockwise, which essentially makes two lasers out of one laser cavity. That, in turn, decreases the number of complex electronics needed to configure two lasers in dual-comb devices, Huang explained.

“We reduce the complexity in the laser design, and we have to compromise the precision a little bit, but it's still much better than the state of art tools used in biomedical applications,” Huang said.

In the team’s most recent Optica paper, they introduced new techniques to reduce the CANDi laser’s relative timing jitter, further proving that the laser will be a good option for a host of applications. That work won PhD student Neeraj Prakash a best poster award at Optica’s 2021 Laser Congress.

Huang said they’ve been working with a startup company in Taiwan that is interested in using CANDi for terahertz imaging – often used in screening for security and drugs. A lab at Colorado State University is also experimenting with the laser for Raman spectroscopy, which has applications in pharmaceuticals and water-quality monitoring.

“CANDi is a new fiber laser architecture and right now, we are working on several projects to unveil its full potential for dual-comb applications,” Huang said.

Read the Optica paper

Shu-Wei Huang and his team are working on a compromise in order to find new applications for a powerful new technology.

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Research collaboration explores multiple methods for brain imaging

Anonymous — Wed, 13 Apr 2022 20:31:33 +0000

Research collaboration explores multiple methods for brain imaging Anonymous (not verified) Wed, 04/13/2022 - 14:31

Researchers at the University of Colorado Boulder and Anschutz Medical Campus are exploring several imaging techniques aimed at creating lightweight miniature microscopes.

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Detailed time-lapse images of brain cells could lead to new insights for neurological disorders

Anonymous — Wed, 30 Mar 2022 13:52:56 +0000

Detailed time-lapse images of brain cells could lead to new insights for neurological disorders Anonymous (not verified) Wed, 03/30/2022 - 07:52

In the journal Biomedical Optics Express, CU researchers describe their new SIMscope3D, a miniature microscope designed for high-resolution 3D images.

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