MURI

New 'vacuum ultraviolet' laser may improve nanotechnology, power nuclear clocks

Steven Burrows — Mon, 16 Mar 2026 17:52:31 +0000

New 'vacuum ultraviolet' laser may improve nanotechnology, power nuclear clocks Steven Burrows Mon, 03/16/2026 - 11:52

Daniel Strain / ��Ҵ�ý�ƽ�� Strategic Communications

Physicists at ��Ҵ�ý�ƽ�� have demonstrated a new kind of vacuum ultraviolet laser that could one day allow scientists to observe phenomena currently out of reach for the most powerful microscopes.

The new laser could allow researchers to follow fuel molecules in real time as they undergo combustion, spot incredibly small defects in nanoelectronics, track time with unprecedented precision and more.

The JILA team will present its preliminary findings on March 17 and March 19 at the American Physical Society Global Physics Summit in Denver.

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Resonant Frequencies: Playing the Edge of Light with a 3-micron Baton

Steven Burrows — Mon, 03 Nov 2025 18:28:05 +0000

Resonant Frequencies: Playing the Edge of Light with a 3-micron Baton Steven Burrows Mon, 11/03/2025 - 11:28

Kenna Hughes-Castleberry / JILA Science Communicator

An ultrastable, scalable and repeatable method for generating soft X-ray beams using a custom-built 3-micron ultrafast laser that is focused into an anti-resonant hollow-core fiber. Image credit: Steven Burrows / JILA

Producing coherent (or laser like) soft X-ray beams in a lab-scale setup represents a many decades-long challenge. Scientists in physics, chemistry, and materials science can use soft X-ray light to study the nanoscale properties of materials and biological systems, to capture behaviors that cannot be seen using visible or even ultraviolet light. But here’s the catch: soft X-rays are notoriously hard to make. To get them, most researchers must travel to large, government-funded synchrotrons—billion-dollar machines, that have limited access and stability. These trips are often rushed, competitive, and only available a few times a year.

Now, a team led by JILA Fellows and ��Ҵ�ý�ƽ�� professors Margaret Murnane and Henry Kapteyn has made a significant advance to make soft X-rays more accessible: with their research group, they have developed an ultrastable, scalable and repeatable method for generating soft X-ray beams using a custom-built 3-micron ultrafast laser that is focused into an anti-resonant hollow-core fiber. This breakthrough, detailed in a paper recently published in APL Photonics, builds on well over a decade of laser development. It presents a technological and experimental advance in high-harmonic generation (HHG), the nonlinear optical process by which high-frequency light is created from lower-frequency driving lasers. The team’s past breakthroughs had shown that the key to generating bright coherent soft X-ray beams was to use mid-infrared (2 – 4 µm) driving lasers focused into a waveguide filled with high-pressure gas. However, no good robust drive lasers existed. In this new breakthrough, the team made giant leaps in transitioning the technique from a heroic optics experiment towards a reliable, applications-oriented light source.

“We wanted to make a coherent X-ray source that doesn’t require a team of optics experts to babysit—something that could find applications in labs across various scientific disciplines and industries,” says JILA research associate Drew Morrill, one of the lead scientists on the project and the paper’s co-first author.
Drew and the team have made a huge step forward by creating bright, ultrastable, coherent soft X-ray beams. In the future, they can enable higher-resolution microscopes that can work in a stroboscopic mode—for example, by capturing nanoscale processes in nanoelectronic, quantum, energy and biological systems, making it possible to understand and optimize them.

A Decade in the Making

Developing JILA’s compact soft X-ray source took over ten years of effort—refining a homebuilt 3-micron wavelength ultrafast laser system when no commercial options existed. From the beginning, the goal was ambitious: to build a mid-infrared laser that was not only powerful and ultrafast but stable enough to operate for entire days without interruption.

To reach that level of performance, the team had to learn how to build fiber lasers from the ground up. That meant mastering delicate tasks like fiber splicing, amplifier construction, and dispersion balancing—adapting technologies initially designed for telecommunications into a new realm of nonlinear fiber optic to seed high power lasers.

One key laser advance came during the early months of the COVID-19 pandemic when the team collaborated with ��Ҵ�ý�ƽ�� Engineering and Physics Professor Scott Diddams. “Scott’s group gave us a roadmap—parts lists, layout guidance, and design principles,” says JILA research scientist Michaël Hemmer, one of the paper’s lead authors. “Then we built it ourselves. The pulses provided by this front-end are outstandingly stable and really the cornerstone of the laser system. These pulses are then amplified using a home-built ytterbium-doped crystal amplifier, providing the high energy needed for HHG while maintaining a clean, controlled beam.”

“The cryogenic ytterbium amplifier is also a second key building block of the system, but it can only run reliably because the front-end is exceptionally reliable; otherwise, it would destroy itself all the time,” notes Hemmer.

Another key contributor was European physicist Dr. Gunnar Arisholm, who shared advanced simulation code that helped the team model complex optical interactions in nonlinear crystals.

“It saved us months of trial and error,” says Hemmer. “He helped train Drew to use the code, which was instrumental in getting the final version running.”

And finally, the key advance was to use optimized waveguides for efficiently converting the laser light into coherent soft X-ray beams.

The line of the first three OPA's that amplify the 3-micron beam. The green light is the parasitic second harmonic light of the 1-micron pump, and the red light is the sum frequency of the 1-micron pump and the 1.5-micron signal. Credit: Gabriella “Gabi” Seifert / JILA

Building and Testing a New Instrument

After designing and re-designing the laser system featuring a fiber-laser-seeded optical parametric chirped-pulse amplifier (OPCPA), the team was finally able to deliver 3 µm wavelength laser pulses with exceptional power and stability. To upconvert this laser light into soft X-rays, the laser pulses are guided through an engineered anti-resonant hollow-core fiber (ARHCF) filled with high-pressure noble gas. Working as a “conductor” for the light, the fiber acts as a waveguide and a container for the interaction medium, allowing the laser and the emitted soft X-rays to travel in phase and interfere constructively over large lengths—opening the door to a new regime of compact, high-brightness sources.

“The laser light travels through the fiber, ionizes the gas, and emits harmonics—overtones of light—far above the frequency of the original beam,” explains JILA graduate student and co-first author Will Hettel.

This process, known as high-harmonic generation (HHG), converts mid-infrared laser pulses into coherent soft X-ray light—similar to how plucking a violin string produces overtones from a single note.

To support this process, the team, with the help of JILA instrument maker and co-author James Uhrich, engineered a precision target system with a modular design: a chassis that allows rapid reconfiguration for different gases and geometries, streamlining the experimental workflow.

“We designed a setup where we can swap out fiber cartridges with micron-level precision,” says Hettel. “It stays aligned even under 10 atmospheres of pressure.”

In terms of output, the system generates soft X-ray photons at energies exceeding 280 eV, reaching the carbon K-edge—a crucial spectral region for biological and materials science applications.

From their design, the researchers found that the setup can run at kilohertz-level repetition rates with continuous, stable beam output for several hours or longer with minimal fluctuation. The system is also rather robust, showing no signs of optical damage even after months of operation. This level of durability is essential for research workflows that demand high uptime and minimal maintenance.

“This isn’t a one-off result,” said Hemmer. “We can run it for days. The beam doesn’t drift. The power doesn’t degrade. That makes it incredibly useful for real experiments.”

Simulating a Symphony

While the laser system was being constructed, another crucial component of the project unfolded in parallel: advanced simulations. To better understand and optimize the HHG process, JILA graduate student Ben Shearer helped develop a fast and flexible numerical model.

“Simulations like this normally take days or weeks to run,” Shearer explains. “We created a version that runs in hours or even minutes—without sacrificing too much of the physics.”

His code, based on a parameterized version of the strong-field approximation, allowed the team to virtually test a wide range of laser pulse durations, energies, and gas conditions before trying them in the lab.

“Ben’s work gave us a cheat sheet,” notes Hemmer. “We could avoid dead ends and prioritize ideas that had a real shot at working.”

These simulations also laid the groundwork for future upgrades, such as transitioning from argon to helium to achieve even higher photon energies.

“If you want to go to the absolute highest energy of high harmonic generation, you need to ionize helium,” says JILA graduate student Gabriella “Gabi” Seifert. “We're getting there; it’s just taking it one step at a time.”

Helium’s higher ionization potential allows stronger driving fields without over-ionizing the medium—a key requirement for pushing HHG to higher energy regimes.

A view of the argon gas cell that the laser is beamed through to produce HHG, showing the fifth harmonic (yellow) and seventh harmonic (blue). Credit: Drew Morrill and Grzegorz Golba / JILA

A World of Possibilities

By building a stable, coherent soft X-ray source that fits on a lab bench, the team has opened the door for broader scientific access to a tool that once required massive infrastructure with limited access.

“We’re really just scratching the surface of what this source can enable,” says Morrill. “With this kind of stability and control, we can start to ask questions that were previously only addressable at synchrotron or free-electron laser facilities, and even go beyond what was possible before.”

Potential applications include high-resolution soft X-ray microscopy of carbon-rich biological material—opening up the possibility of live cell imaging without the need to add light-emitting fluorescent molecules or without the need to freeze the sample.

“This spectral regime is well suited for high-resolution biological imaging,” says JILA graduate student Clay Klein
Other uses lie in probing advanced magnetic materials, such as those explored for ultra-low-energy computing or data storage technologies based on electron spin.

“There’s a long history of new light sources unlocking unexpected science,” said Morrill. “We’re excited to see where this one leads.”

This research was published in APL Photonics.

A team led by JILA Fellows and ��Ҵ�ý�ƽ�� professors Margaret Murnane and Henry Kapteyn has made a significant advance to make soft X-rays more accessible: with their research group, they have developed an ultrastable, scalable and repeatable method for generating soft X-ray beams using a custom-built 3-micron ultrafast laser that is focused into an anti-resonant hollow-core fiber.

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JILA Graduate Students Anya Grafov and Iona Binnie Receive Top Honors at MMM Intermag 2025 Conference

Steven Burrows — Mon, 17 Feb 2025 17:16:52 +0000

JILA Graduate Students Anya Grafov and Iona Binnie Receive Top Honors at MMM Intermag 2025 Conference Steven Burrows Mon, 02/17/2025 - 10:16

Kenna Hughes-Castleberry / JILA Science Communicator

JILA graduate student Anya Grafov (second to the right) holds up her award for Best Lightning Talk.

Congratulations to JILA graduate students Anya Grafov and Iona Binnie—who conduct their cutting-edge research in the laboratory of JILA Fellows and the University of Colorado Boulder professors Margaret Murnane and Henry Kapteyn—for their outstanding achievements at the MMM Intermag 2025 conference!

“I'm grateful to the IEEE Magnetics Society for the opportunity to share my research and honored to be recognized,” said Grafov. “The Young Professionals Lightning Talks required us to present our research to a general audience in just two minutes. Ultrafast magnetism and extreme ultraviolet light science are complex topics, so explaining my entire project in such a short time was no easy task. Summarizing my project without jargon or lengthy explanations was a rewarding challenge that strengthened my science communication skills.”

JILA graduate student Iona Binnie (right) holds up her certificate for Best Poster

Grafov earned 1st Place in the Young Professionals Lightning Talks for her presentation, “Measuring Magnetic Dynamics with Extreme Ultraviolet Light,” while Binnie won the Best Poster Award in her session for her poster, “Probing Skyrmions via High Harmonic Driven Ultrafast Magnetic Scattering and Coherent 3D X-ray Vector Ptychography.”

“Presenting my poster was a demanding but very rewarding experience,” added Binnie. “I really enjoyed the opportunity to share my research with the magnetics community, which is a different audience than I am used to. Their questions sparked new insights into my own research challenges.”

Their achievements showcase the innovative work happening at JILA in the fields of ultrafast magnetism and extreme ultraviolet light science.

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Diamonds are Forever—But Not in Nanodevices

Steven Burrows — Thu, 23 Jan 2025 20:05:16 +0000

Diamonds are Forever—But Not in Nanodevices Steven Burrows Thu, 01/23/2025 - 13:05

Kenna Hughes-Castleberry / JILA Science Communicator

A diffractive optic creates two DUV beams, which are focused and interfered on a sample surface (diamond) using a 4f imaging system to generate a microscopic sinusoidal excitation profile. Image credit: Steven Burrows

Ultrawide-bandgap semiconductors—such as diamond—are promising for next-generation electronics due to a larger energy gap between the valence and conduction bands, allowing them to handle higher voltages, operate at higher frequencies, and provide greater efficiency compared to traditional materials like silicon. However, their unique properties make it challenging to probe and understand how charge and heat move on nanometer-to-micron scales. Visible light has a very limited ability to probe nanoscale properties, and moreover, it is not absorbed by diamond, so it cannot be used to launch currents or rapid heating.

Now, researchers at JILA, led by JILA Fellows and University of Colorado physics professors Margaret Murnane and Henry Kapteyn, along with graduate students Emma Nelson, Theodore Culman, Brendan McBennett, and former JILA postdoctoral researchers Albert Beardo and Joshua Knobloch, have developed a novel microscope that makes examining these materials possible on an unprecedented scale. The team’s work, recently published in Physical Review Applied, introduces a tabletop deep-ultraviolet (DUV) laser that can excite and probe nanoscale transport behaviors in materials such as diamond. This microscope uses high-energy DUV laser light to create a nanoscale interference pattern on a material’s surface, heating it in a controlled, periodic pattern. Observing how this pattern fades over time provides insights into the electronic, thermal, and mechanical properties at spatial resolutions as fine as 287 nanometers, well below the wavelength of visible light.

Murnane states that this new probe capability is important for future power electronics, high-frequency communication, and computational devices based on diamond or nitrides rather than silicon. Only by understanding a material's behavior can scientists address the challenge of short lifetimes observed in many nanodevices incorporating ultrawide-bandgap materials.

A Challenge from an Industry Partner

For Nelson and the other JILA researchers, this project began with an unexpected challenge from materials scientists from one of their industry collaborators: 3M.

“3M approached us to study an ultrawide material sample that wasn’t compatible with our existing microscopes,” Nelson says. The team then collaborated with 3M scientists Matthew Frey and Matthew Atkinson to build a microscope that could image transport in this material.

Traditional imaging methods rely on visible light to see the microscopic composition and transport behaviors in semiconductors and other materials, which is effective for studying materials with smaller bandgaps.

However, materials like diamond, often used in electronic components, have a much larger energy gap between their valence and conduction bands—typically exceeding 4 electron volts (eV)—making them transparent to lower-energy visible and infrared light. Higher-energy photons in the ultraviolet (UV) range or beyond are required to interact with and excite electrons in these materials.

Visible-light setups also struggle with spatial resolution, as their longer wavelengths limit theability to probe the nanoscale dimensions relevant to modern devices.

These limitations inspired the team to think outside the box for their imaging setup.

“We brainstormed a new experiment to expand what our lab could study,” says Nelson.

The result was a multi-year effort to develop a compact microscope that uses DUV light to generate nanoscale heat patterns on a material’s surface without altering the material itself.

Diving into the Deep Ultraviolet Regime

To generate the DUV light, the team first started with a laser emitting pulses at an 800-nanometer wavelength. Then, by passing laser light through nonlinear crystals and manipulating its energy, the team converted it step-by-step into shorter and shorter wavelengths, ultimately producing a powerful deep-ultraviolet light source at around 200 nanometers wavelength.

Each step required precise alignment of laser pulses in space and time within the crystals to achieve the desired wavelength efficiently.

“It took a few years to get the experiment working during the pandemic,” says Nelson, describing the trial-and-error process of aligning light through three successive crystals. “But once we had the setup, we could create patterns on a scale never before achieved on a tabletop.”

To produce the periodic pattern, called a transient grating, the researchers split the DUV light into two identical beams using a diffraction grating. These beams were directed onto the material’s surface at slightly different angles, where they overlapped and interfered with each other, forming a precise sinusoidal pattern of alternating high and low energy. This interference pattern acted as a nanoscale “grating,” temporarily heating the material in a controlled way and generating localized energy variations.

This process allowed the team to study how heat, electrons, or mechanical waves—depending on the material—spread and interacted across the nanoscale grating. The periodicity of the grating, which defined the distance between these high-energy peaks, was closely related to the wavelength of the light source, allowing researchers to get shorter periods by using higher energy (and shorter wavelength) light. The periodicity could be tuned by adjusting the angles of the beams, enabling detailed studies of transport phenomena at microscopic scales. For example, in this experiment, the team achieved grating patterns as delicate as 287 nanometers, a record for laser tabletop setups.

Testing the New DUV Microscope

Once the DUV transient grating system was operational, the team focused on validating its accuracy and exploring its capabilities. Their first test involved thin gold films, which served as a benchmark material due to their well-understood properties. The researchers used their system to generate nanoscale heat patterns, launching acoustic waves at the film’s surface. By analyzing the frequency and behavior of these waves, they extracted material properties such as density and elasticity.

To confirm their results, Nelson developed computer models simulating how the gold film would behave under similar conditions. The experimental data matched her predictions closely, providing a strong validation of the system’s precision.

“Seeing the experiment work and align with the models we created was a relief and an exciting milestone,” Nelson says.

Next, the team used their new DUV microscope to look at diamond, a material prized for its exceptional electronic and thermal properties. Previous techniques for studying diamond often required physical alterations, such as adding nanostructures or coatings, which inadvertently changed its properties. The DUV system eliminated this need, enabling the team to study diamond in its pristine state.

Using their new setup, the researchers observed how charge carriers—electrons and holes—diffused across the diamond after being excited by the DUV light. This process revealed new insights into the nanoscale transport dynamics of diamonds, particularly at nanometer scales.

Beyond validating the system and exploring diamond’s properties, the team’s findings shed light on broader questions of nanoscale heat transport. At such small scales, heat doesn’t always behave as predicted by traditional physical models, which assume a smooth, continuous flow. Instead, nanoscale transport can involve ballistic and hydrodynamic effects, where energy carriers like phonons can travel in a straight line without scattering or can spread like water flowing through channels.

As researchers continue to refine these techniques and explore new materials, this advancement could play a crucial role in the development of high-performance power electronics, efficient communication systems, and quantum technologies. In the quest to push the boundaries of modern devices, diamonds may not last forever—but their impact on nanoscience certainly will.

This research was supported by the STROBE Science and Technology Center and 3M.

Researchers at JILA have developed a novel microscope that makes examining ultrawide-bandgap semiconductors possible on an unprecedented scale. The team’s work, recently published in Physical Review Applied, introduces a tabletop deep-ultraviolet (DUV) laser that can excite and probe nanoscale transport behaviors in materials such as diamond. This microscope uses high-energy DUV laser light to create a nanoscale interference pattern on a material’s surface, heating it in a controlled, periodic pattern. Observing how this pattern fades over time provides insights into the electronic, thermal, and mechanical properties at spatial resolutions as fine as 287 nanometers, well below the wavelength of visible light.

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JILA Graduate Student Clay Klein Awarded 2025 Nick Cobb Memorial Scholarship

Steven Burrows — Tue, 14 Jan 2025 17:40:43 +0000

JILA Graduate Student Clay Klein Awarded 2025 Nick Cobb Memorial Scholarship Steven Burrows Tue, 01/14/2025 - 10:40

Kenna Hughes-Castleberry / JILA Science Communicator

JILA graduate student Clay Klein has been awarded the 2025 Nick Cobb Memorial Scholarship by SPIE

JILA graduate student Clay Klein has been awarded the prestigious 2025 Nick Cobb Memorial Scholarship, presented by SPIE, the International Society for Optics and Photonics, and Siemens EDA. The scholarship, valued at $10,000, recognizes Klein’s outstanding contributions to the field of optics and photonics.

“I am honored to be awarded the Nick Cobb Memorial Scholarship,” Klein stated. “This scholarship provides me with the exciting opportunity to share my research in this field and connect with others in the industry at the SPIE conference in February.”

Klein conducts research in the laboratories of JILA Fellows and University of Colorado Boulder Physics professors Margaret Murnane and Henry Kapteyn. His work focuses on cutting-edge advancements in nanoscale extreme ultraviolet imaging science.

The award will be formally presented during the Welcome and Plenary Presentation at the SPIE Advanced Lithography + Patterning Conference in San Jose, California, on February 24, 2025. Congratulations Clay!

Read the full SPIE press release here

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JILA Graduate Student Emma Nelson Wins Third Place at the 2024 ��Ҵ�ý�ƽ�� Innovation in Materials Symposium

Steven Burrows — Fri, 16 Aug 2024 19:07:59 +0000

JILA Graduate Student Emma Nelson Wins Third Place at the 2024 ��Ҵ�ý�ƽ�� Innovation in Materials Symposium Steven Burrows Fri, 08/16/2024 - 13:07

Kenna Hughes-Castleberry / JILA Science Communicator

JILA graduate student Emma Nelson (left, wearing red) claps as the award winners are announced at the ��Ҵ�ý�ƽ�� Innovation in Materials Symposium 2024. Credit: Emma Nelson

JILA and University of Colorado Boulder Physics graduate student Emma Nelson achieved notable recognition by securing 3rd place at the ��Ҵ�ý�ƽ�� 2024 Innovation in Materials Symposium on August 15, 2024. Held at ��Ҵ�ý�ƽ��, this symposium is a significant platform for the materials research community, bringing together faculty, students, and industry professionals from ��Ҵ�ý�ƽ�� and beyond. The event is dedicated to supporting interdisciplinary collaboration and furthering discussions in the field of materials science.

"The competition was a great opportunity to share my team's exciting research with the materials science community,” Nelson stated.

Nelson, who works under the guidance of JILA Fellows and ��Ҵ�ý�ƽ�� Physics professors Margaret Murnane and Henry Kapteyn, presented her research on extreme ultraviolet (EUV) light. Her work focuses on leveraging EUV light for high-resolution microscopic imaging, a cutting-edge approach that has garnered considerable attention in the scientific community. Congratulations to Emma Nelson!

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JILA Graduate Student Anya Grafov is Awarded Best Poster From the IEEE Magnetics Society Summer School 2024

Steven Burrows — Thu, 20 Jun 2024 19:38:21 +0000

JILA Graduate Student Anya Grafov is Awarded Best Poster From the IEEE Magnetics Society Summer School 2024 Steven Burrows Thu, 06/20/2024 - 13:38

Kenna Hughes-Castleberry / JILA Science Communicator

JILA graduate student Anya Grafov stands with her best poster award at the IEEE Magnetics Society Summer School in Taiwan. Credit: Anya Grafov

Anya Grafov, a graduate student at JILA, has been awarded the Best Poster Award at the IEEE Magnetics Society Summer School 2024. Studying under JILA Fellows and University of Colorado Boulder Physics professors Margaret Murnane and Henry Kapteyn, Grafov's poster titled “Probing Ultrafast Spin Dynamics with Extreme Ultraviolet High Harmonics” was one of only nine to receive this prestigious recognition.

“Winning this award from the IEEE Magnetics Society is an incredible honor. It validates the hard work and dedication put into our research and motivates us to continue pushing the boundaries in magnetics research,” stated Grafov. “Our technique is quite niche, so I wanted to focus my poster on our actual measurement technique and the experiments we conduct. It's an overview of the measurement technique and examples of two recent projects we've been working on using our beamline.”

Highlighting the fundamentals and new research, like Grafov’s, in magnetics, the annual summer school brings together graduate students worldwide to study magnetism through lectures by international experts and poster presentations.

“It was a great experience to learn about different aspects of magnetism, from fundamental research to applied technologies like spintronic devices and magnetic artificial intelligence,” she added.

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JILA Graduate Student Yunzhe “Oliver” Shao Wins Best Paper Award at the IEEE Conference on Computational Imaging Using Synthetic Apertures

Steven Burrows — Thu, 20 Jun 2024 16:39:50 +0000

JILA Graduate Student Yunzhe “Oliver” Shao Wins Best Paper Award at the IEEE Conference on Computational Imaging Using Synthetic Apertures Steven Burrows Thu, 06/20/2024 - 10:39

Kenna Hughes-Castleberry / JILA Science Communicator

Oliver Shao has been awarded the Best Paper Award at the IEEE Conference on Computational Imaging Using Synthetic Apertures. Image credit: Oliver Shao.

Yunzhe “Oliver” Shao, a graduate student at JILA in the group led by JILA Fellows and University of Colorado Boulder Physics professors Margaret Murnane and Henry Kapteyn, has been awarded the Best Paper Award at the IEEE Conference on Computational Imaging Using Synthetic Apertures.

Shao's winning research focused on developing an extreme ultraviolet (EUV) reflectometer. This innovative instrument is designed to characterize various nanostructured samples' chemical compositions and spatial properties.

"This research represents a first-iteration, proof-of-concept instrumentation for nanostructure metrology," Shao explained. "It has been constructed, developed, and improved over several generations of graduate students in our group. It is reassuring and inspiring to share its new capabilities and witness the interest it generates from the metrology community."

The paper was submitted to the 2024 IEEE Conference on Computational Imaging Using Synthetic Apertures, created in partnership with and hosted by NIST (the National Institute of Standards and Technology). The annual event highlights advancements in cutting-edge computer imaging and sensing using high-resolution imaging systems, like the reflectometer Shao and the KM group work on.

Shao expressed gratitude for the recognition, highlighting the collective effort behind the project. "Apart from its founding members, whose names are listed in several previous publications, the reflectometer does not exist without the continuing efforts of current students and postdocs from our group, including Nick Jenkins, Clay Klein, Yunhao Li, and Jiayi Liu. We are motivated to further develop and improve this metrology instrument beyond its current limitations."

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JILA Graduate Student Nick Jenkins Wins Prestigious Nick Cobb Memorial Scholarship

Steven Burrows — Thu, 14 Dec 2023 18:56:47 +0000

JILA Graduate Student Nick Jenkins Wins Prestigious Nick Cobb Memorial Scholarship Steven Burrows Thu, 12/14/2023 - 11:56

Kenna Hughes-Castleberry / JILA Science Communicator

JILA graduate student Nick Jenkins adjusts a setting on his laser tabletop setup.

Nick Jenkins, a graduate student at JILA, an institute jointly operated by the University of Colorado Boulder and the National Institute of Standards and Technology (NIST), has been awarded the esteemed Nick Cobb Memorial Scholarship. Mentored by JILA Fellows and University of Colorado Boulder professors Margaret Murnane and Henry Kapteyn, Jenkins' research focuses on pioneering tabletop extreme ultraviolet (EUV) microscopy techniques using high-harmonic generation light sources. This innovative work has positioned him as a standout recipient of this significant award.

The Nick Cobb Memorial Scholarship, valued at $10,000, is an annual grant given to an exceptional graduate student studying advanced lithography or a related field. The scholarship, jointly funded by Siemens EDA and SPIE, is more than just financial support. It covers a range of educational expenses, including tuition and fees, textbooks, supplies, and even computer equipment necessary for academic pursuits.

Jenkins' work in EUV microscopy is not just academically excellent but also aligns closely with the technological and innovative spirit of the scholarship. His research under the guidance of Professors Murnane and Kapteyn at JILA is breaking new ground in the field of lithography, contributing to the development of advanced imaging techniques that could revolutionize various technological sectors.

Jenkins' achievement is a testament to his hard work and dedication to his research. It also highlights the supportive and innovative environment at JILA, fostering groundbreaking research in advanced lithography. This scholarship acknowledges Jenkins' accomplishments and supports his future EUV microscopy and lithography endeavors.

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Creating the “Goldilocks” Zone: Making Special-Shaped Light

Steven Burrows — Thu, 16 Nov 2023 17:54:18 +0000

Creating the “Goldilocks” Zone: Making Special-Shaped Light Steven Burrows Thu, 11/16/2023 - 10:54

Kenna Hughes-Castleberry / JILA Science Communicator

Two different powered polarized lasers combine in the process of High Harmonic Generation. Image credit: Steven Burrows / JILA

In a new study published in Scientific Reports, JILA Fellow and University of Colorado Boulder physics professor Andreas Becker and his team theorized a new method to produce extreme ultraviolet (EUV) and x-ray light with elliptical polarization, a special shape in which the direction of light waves’ oscillation is changing. This method could provide experimentalists with a simple technique to generate such light, which is beneficial for physicists to further understand the interactions between electrons in materials on the quantum level, paving the way for designing better electronic devices such as circuit boards, solar panels, and more.

Many physicists use a process called High-harmonic Generation (HHG) as a source to generate ultrashort EUV and x-ray laser light and use this light to study the ultrafast dynamics of charged particles in different materials. By shooting high-powered laser pulses into a gas of atoms, the researchers can force the atoms to absorb the photons from the laser pulses. This causes the electrons in the atoms to jump to a higher energy level, then fall back to the ground level and emit energy as the atoms radiate in integral multiples of the laser frequency.
JILA graduate student and first author Bejan Ghomashi explained that “these [energies] will be the harmonics. So, if an 800-nanometer light is absorbed, it’s also emitted, along with 400 nanometers, 200 nanometers, etc.”

This process can be conveniently performed within a tabletop laser setup, as pioneered in the laboratories of JILA Fellows Margaret Murnane and Henry Kapteyn. It gives scientists a relatively cost-effective option to learn more about ultrafast electron dynamics.

“More people have access to an idea and can explore it,” Becker added.

Creating Polarization States of Light

Light polarization is a way to describe the direction in which light waves are oscillating. More specifically, polarization describes in which direction the oscillation of the electric field of the light in a laser beam varies over time. For example, the light’s electric field may wiggle along a line, making it linearly polarized. In other cases, the direction of the wiggling electric field may rotate, making the light circularly polarized. Creating light in which the electric field varies along an elliptical shape is a middle-ground between pure linearly and circularly polarized light.

Historically, it has however been challenging to produce elliptically polarized HHG light, but in this new study, Becker and his team explored how to use two linearly cross-polarized lasers at differing frequencies and directions to produce this desired shape. Unlike other, more complex, methods proposed to generate elliptically polarized HHG, an experimental set-up with two cross-polarized laser pulses interacting with an atomic gas is relatively simple.

Sources of elliptically polarized X-ray and EUV light can be useful in helping to study chiral and magnetic materials, as their electrons are sensitive to the direction of applied laser fields. Chiral materials, or materials with a special symmetry, are commonly found in foods and medicines. An example is aspartame sweetener: the left-handed version is sweet, while the right-handed version is not.

Resolving An Odd Puzzle

While previous theories had postulated that it is impossible to create elliptically polarized light using the configuration of two cross-polarized pulses, in 2015, an experimental study produced that exact result. Ghomashi elaborated: “At the time, theoretical physics had no explanation for the ellipticity generated in this experiment and argued it, in fact, should not exist. This was a puzzle to be resolved.”

Intrigued by this discrepancy, Ghomashi, recently graduated JILA Ph.D. student Spencer Walker, and Becker developed a method to analyze the experimental set-up in computer simulations. The results of those simulations produced the same results as found in the 2015 experiment for certain sets of parameters of the two cross-polarized laser pulses.

“You must find what we call the ‘sweet spot’—it is not just one parameter—but you have to tune several parameters simultaneously,” added Ghomashi.

Besides fiddling with the pulse length of the lasers, the researchers also fine-tuned the intensity (or the peak electric fields) of the two laser beams, where one beam was more intense than the other. The result of manipulating these two parameters created a “Goldilocks zone” for producing the rare, elliptically-shaped HHG light.

Walker elaborated that “by reducing the pulse duration, we control the amount of radiation in both [the x and y] directions simultaneously. And if you have emission in both directions at the right energy, you have ellipticity.”

Because of this method’s simplicity, the researchers hope that it will be possible for other physicists to reproduce their results in an experimental setup in order to validate their theoretical interpretation.

“It resolves an odd puzzle in the science community,” Becker stated, “which is always important for scientists and researchers.”

As JILA Fellows Margaret Murnane and Henry Kapteyn develop some of the world's most precise table-top laser setups, testing the team’s concept at JILA would also be possible. “The mechanism, so how to change the knobs and why adjusting the parameters achieves the outcome, is very straightforward,” Walker said. “It's just a matter of the details.”

In a new study published in Scientific Reports, JILA Fellow and University of Colorado Boulder physics professor Andreas Becker and his team theorized a new method to produce extreme ultraviolet (EUV) and x-ray light with elliptical polarization, a special shape in which the direction of light waves’ oscillation is changing. This method could provide experimentalists with a simple technique to generate such light, which is beneficial for physicists to further understand the interactions between electrons in materials on the quantum level, paving the way for designing better electronic devices such as circuit boards, solar panels, and more.

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