STROBE in the News

New CU Boulder research harnesses the power of an ultrafast microscope to study molecular movement in space and time.

The interactions in photovoltaic materials that convert light into electricity happens in femtoseconds. How fast is that? One femtosecond is a quadrillionth of a second­­. To put that in perspective, the difference between a second and a femtosecond is comparable to the difference between the second right now and 32 million years ago.

Subatomic particles like electrons move within atoms, and atoms move within molecules, in femtoseconds. This speed has long presented challenges for researchers working to make more efficient, cost-effective and sustainable photovoltaic materials, including solar cells. Imaging materials on the nanoscale with high enough spatial resolution to uncover the fundamental physical processes poses an additional challenge.

Understanding how, where and when electrons move, and how their movement depends on the molecular structure of these materials, is key to honing them or developing better ones.

Building on more than five years of research developing a unique ultrafast microscope that can make real-time “movies” of electron and molecular motion in materials, a team of University of Colorado Boulder scientists published in Science Advances the results of significant innovations in ultrafast nanoimaging, visualizing matter at its elementary atomic and molecular level.

The research team, led by Markus Raschke, professor of physics and JILA fellow, applied the ultrafast nanoimaging techniques they developed to novel perovskite materials. Perovskites are a family of organic-inorganic hybrid materials that are efficient at converting light to electricity, generally stable and relatively easy to make…

UCLA physicist John Miao pioneered a new form of microscopy with unprecedented precision and field of view.  In 1999, then-graduate student Jianwei “John” Miao and his colleagues at the State University of New York, Stony Brook, demonstrated that a computational algorithm, combined with patterns of scattered photons, could reveal miniscule details previously impossible to capture with conventional microscopes.

Building on an established method for determining atomic structures called X-ray crystallography, they expanded its application to structures that lack the uniform, repeating patterns found in crystals. The algorithm reconstructs images from diffraction patterns — the arrangement of electromagnetic beams after they are bent and scattered as they pass through samples. This technique diverges from traditional microscopy by combining diffraction and computation to effectively replace the objective lens.

If you imagine microscopes as computer hardware, Miao’s approach is the “killer app” that unlocks their full potential. Over the past 25 years, scientists have integrated this approach into different types of microscopes, driving the field of computational microscopy to achieve unparalleled resolution and precision, and to capture the broadest fields of view yet on samples under investigation. These advances have led to brand-new insights into the structure and behavior of catalysts, superconductors, computer chips and next-generation batteries and materials…

New tool removes motion artifacts when imaging dynamic samples. Imaging microscopic samples requires capturing multiple, sequential measurements, then using computational algorithms to reconstruct a single, high-resolution image. This process can work well when the sample is static, but if it’s moving — as is common with live, biological specimens — the final image may be blurry or distorted.

Now, Berkeley researchers have developed a method to improve temporal resolution for these dynamic samples. In a study published in Nature Methods, they demonstrated a new computational imaging tool, dubbed the neural space-time model (NSTM), that uses a small, lightweight neural network to reduce motion artifacts and solve for the motion trajectories.

One of the first experimenters at the new flagship US laser, Michigan alum Franklin Dollar’s mission is bigger than research.

When the first beam of light ran through a laser system that will be the most powerful in the U.S., it was delivered to an experiment designed by an old hand at U-M’s Center for Ultrafast Optical Sciences.

As a graduate student in the late 2000s, Franklin Dollar (MSE Electrical Engineering ’10, PhD Applied Physics ’12) built experiments at HERCULES, the most intense laser in the world at the time. HERCULES has now been upcycled into ZEUS, the Zetawatt-Equivalent Ultra-short laser pulse System—which will offer triple the power of the next largest US lasers. Its peak power is three petawatts, or more than 100 times global electricity production, but only for a few quintillionths of a second.

Dollar has stayed connected with the lab, leading experiments in late 2022, early 2023 and January this year that the ZEUS team used to work out the bugs in the system. Then earlier this month, he led ZEUS’s first official experiment in the flagship target area, where the signature zetawatt-equivalent experiments will take place.

Thanks to the PEAQS program, Max Krauss (Computer Engineering, ’24), got to sharpen his skills in research and peer research publication before heading to University of Utah for a doctoral program. From tinkering with electronics as a child to tackling advanced nanofabrication in graduate school, Max Krauss’ (Computer Engineering, ‘24) is a story of curiosity, innovation, and transformative learning.

The Partnership for Education and the Advancement of Quantum and nanoSciences recently received its second, six-year $4.2 million grant from the National Science Foundation. Fort Lewis College second-year student Sharelle Yazzie —a pre-med major— never thought she would be interested in research. A transfer student from Diné College, she was checking out different opportunities at FLC when she met Izzy Lamb, assistant professor of Chemistry at FLC, who told her about his work throughout the PEAQS program.

New awards from the NSF Partnerships for Research and Education in Materials program will strengthen research infrastructure and education pathways at 15 minority-serving institutions, including six in EPSCoR states.

The U.S. National Science Foundation is announcing $50 million in Partnerships for Research and Education in Materials (PREM) awards to 15 collaborative research projects nationwide to expand participation and access to materials science-focused facilities, education, training and careers.

NSF is investing over $50 million in total, which includes awards of over $4 million each to 11 partnering institutions over six years and $1 million in seed funding to each of four additional institutions over three years.

“Supporting the scientific talent present in every community in our country is imperative to strengthening the nation’s materials research infrastructure, which is central to everything from semiconductors to medical implants,” said NSF Director Sethuraman Panchanathan. “NSF is dedicated to empowering everyone who wants to shape our scientific future for the benefit of their communities and the U.S. research community at large.”

Since 2004, the NSF PREM program has broadened access to materials science-focused skills and opportunities by supporting strategic partnerships between minority-serving institutions and NSF-funded research centers and facilities at research-intensive institutions.

In addition to fundamental materials research projects, the new PREM awards will support specialized training and mentorship for students and early-career researchers, new research faculty positions, expanded educational outreach to local high school students and teachers, and other activities to build pathways for the future materials research workforce. Six awards are to institutions located in states that receive less federal funding than others and participate in the Established Program to Stimulate Competitive Research.

The 2024 PREM awardees:

Partnership for Education and Advancement of Quantum and nano-Sciences at Fort Lewis College and Norfolk State University, in partnership with the Science and Technology Center for Integration of Modern Optoelectronic Materials on Demand at the University of Washington, will directly support over 80 undergraduate and high school students at Fort Lewis College, a non-tribal Native American-serving institution in Durango, Colorado, and Norfolk State University, a historically Black university in Virginia. Research focus: quantum-level material properties with potential applications in materials fabrication and nanoscale devices such as nanotherapeutics for biomedical purposes.

Alloys, which are materials such as steel that are made by combining two or more metallic elements, are among the underpinnings of contemporary life. They are essential for buildings, transportation, appliances and tools — including, very likely, the device you are using to read this story. In applying alloys, engineers have faced an age-old trade-off common in most materials: Alloys that are hard tend to be brittle and break under strain, while those that are flexible under strain tend to dent easily.

Possibilities for sidestepping that trade-off arose about 20 years ago, when researchers first developed medium- and high-entropy alloys, stable materials that combine hardness and flexibility in a way in which conventional alloys do not. (The “entropy” in the name indicates how disorderly the mixture of the elements in the alloys is.)

In a new study, researchers at CU Boulder have used doughnut-shaped beams of light to take detailed images of objects too tiny to view with traditional microscopes.

The new technique could help scientists improve the inner workings of a range of “nanoelectronics,” including the miniature semiconductors in computer chips. The discovery was highlighted Dec. 1 in a special issue of Optics & Photonics News called Optics in 2023.

The research is the latest advance in the field of ptychography, a difficult to pronounce (the “p” is silent) but powerful technique for viewing very small things. Unlike traditional microscopes, ptychography tools don’t directly view small objects. Instead, they shine lasers at a target, then measure how the light scatters away—a bit like the microscopic equivalent of making shadow puppets on a wall.

So far, the approach has worked remarkably well, with one major exception, said study senior author and Distinguished Professor of physics Margaret Murnane.

“Until recently, it has completely failed for highly periodic samples, or objects with a regularly repeating pattern,” said Murnane, fellow at JILA, a joint research institute of CU Boulder and the National Institute of Standards and Technology (NIST). “It’s a problem because that includes a lot of nanoelectronics.”

Lensless imaging based on ptychographic coherent diffractive imaging enables diffraction-limited microscopy at short wavelengths, overcoming the limits of imperfect optics.^1,2 Ptychographic imaging of highly periodic structures has been challenging, however, due to the lack of diversity in the recorded diffraction patterns, which leads to poor convergence of the reconstructed sample images. Although techniques (such as modulus enforced probe and total variation regularization) have been explored to address this challenge, they suffer from slow convergence, heavy reliance on constraints on the samples, or both. This significantly limits ptychography’s application to a wide variety of periodic structures in photonics, nanoelectronics and extreme ultraviolet (EUV) photomasks.