Two of the best-kept secrets in the University of Maryland’s Department of Physics are its Vortex Makerspace and a small class held in the makerspace that is dedicated to the practical skills needed for physics experimentation.

Since 2019, Professor Daniel Lathrop has taught a unique 400-level laboratory course in the Vortex Makerspace (formerly the Physics Welding Shop), which is tucked behind the John S. Toll Physics Building. Designed to teach students hands-on ways to bring their ideas to life, the class touches on topics such as carpentry, circuitry and 3D printing. Lathrop guides the students as they design, plan, build and demo their creations inspired by the semester’s physics lecture topics. But it’s not all about a student’s ability to build from scratch, Lathrop said.

“One thing I really wanted to accomplish with this class was to expose students to skills that they wouldn’t usually come across in their conventional classroom studies,” Lathrop explained. “That not only includes how to make things with their hands but also how to develop soft skills like leadership, budgeting, communication and teamwork—all qualities that are needed in real-life careers in physics.”

To simulate the kinds of situations, goals and challenges that physics experimentalists often encounter, Lathrop wove together 12 weeks of interactive lectures, field trips, training sessions and demonstrations. As his unique lesson plans for the class quickly spread by word of mouth, physics majors eager for a more hands-on learning experience registered for the class.

One of those students, Alexandra Pick-Aluas (B.S. ’22, physics), first heard glowing reviews about Lathrop’s class from two friends and was intrigued by the prospect of a lab elective that could give her a sneak peek into the professional future she hoped to pursue. She realized quickly that the class was unlike any she’d ever taken. 

“We were given an introduction to welding, which was obviously something I never tried before,” Pick-Aluas explained. “I learned how to weld pieces of metal together and got to see the difference in outcomes for the different metals I used. For example, aluminum is really easy to melt and that’s one reason why it’s a notoriously difficult metal to weld. It’s one thing to read about it, but it’s a much more enlightening experience to actually see it in action in front of me.”PHYS 499X students demonstrate their Spring 2022 semester project, a liquid nitrogen-cooled superconducting loop. From left to right: Peiyu Qin, Alexandra Pick-Aluas, Meyer Taffel, Noah Doney, Ankith Rajashekar, Brian Robbins, and Dylan Christopherson. Image courtesy of Daniel Lathrop.

Welding was just one skill Pick-Aluas developed during the class. For their final project, Pick-Aluas and her group members built a superconducting loop—an infinitely flowing electric current with no power source—with materials like scrap metal, a bicycle wheel spoke and superconducting tape. Guided by Lathrop, they designed a suitable prototype within a limited budget, ordered their required materials from specialized vendors, constructed their design and wrote a manual explaining how their project functioned.  

“Even though our project didn’t exactly work the way we originally wanted it to, the entire process it took to make the superconducting loop is something I’ll always remember,” Pick-Aluas said. “Professor Lathrop says that in reality, failures and setbacks should be expected before making progress.”

She hopes that more physics majors take PHYS 499X before they graduate. For Pick-Aluas, who is now assisting Lathrop in his lab as she prepares for graduate school, the expertise she gained from the course helped shape her own career goals. 

“At first, I was a little intimidated, but the class made me feel a lot more comfortable with these skills. Potentially applying them on the job is a little less daunting to me now,” Pick-Alaus explained. “PHYS 499X is a really good overview of what you can expect in a real-life physics-related profession, whether it’s in academia or in industry.” 

Beyond the class, physics majors can also use the Vortex Makerspace—which is housed within the same single-room building as PHYS 499X—for all their experimentalist aspirations. Thanks to key efforts from UMD Physics Director of Education Donna Hammer, Vortex provides a dedicated time and place for students to work on meaningful projects of their own. Equipped with saws, welders, wires, wrenches and other knickknacks ready for students to use, the makerspace also encourages students to walk in and chat with Vortex’s ‘shop managers’ if they need additional guidance, resources or someone to simply bounce ideas off of.

“We’re open four afternoons a week to anyone during the semester—no experience or background necessary,” said Jake Lyon, a senior physics major and vice president of the Vortex Makerspace. “Vortex frequently holds training sessions and workshops for a variety of topics, like intro into basic coding or circuitry.”

Jake Lyon (right) teaches a student how to solder a simple circuit at the UMD Physics Vortex Makerspace.Lyon became involved with the makerspace as a sophomore. Over the next few years, he attended a variety of training sessions and eventually developed an arsenal of handy skills from 3D printing to soldering. Then he tested this newly acquired knowledge, applying it to the projects he took on at the makerspace, including his personal favorite, fixing a broken megaphone. He believes taking the megaphone apart, figuring out how it worked and diagnosing what went wrong was an experience that will stay with him long after he graduates.

“The Vortex is a fantastic place to learn and get comfortable with the basic parts of fabrication with the right equipment while also getting to know the physics makers community,” Lyon said. “We facilitate learning but try to encourage teamwork and communication with everyone as well.”

In addition to the activities held during the semester, the Vortex Makerspace also offers a series of summer programs, including the Physics Makers Camp for high school students looking to get a head start on creative thinking and design, run by Outreach Coordinator Angel Torres. And although Vortex is run by physics undergraduates, Lyon said the organization welcomes anyone who wants to bring a project to life.

“We have a good lineup of ideas for workshops in the spring semester, so anyone—including non-physics majors—looking to acquire a new handy skill or two is welcome to stop by,” Lyon said. “Just bring an idea and we’ll bring the tools.” 

Written by Georgia Jiang 

It's not at every university that laser pulses powerful enough to burn paper and skin are sent blazing down a hallway. But that’s what happened in UMD’s Energy Research Facility, an unremarkable looking building on the northeast corner of campus. If you visit the utilitarian white and gray hall now, it seems like any other university hall—as long as you don’t peek behind a cork board and spot the metal plate covering a hole in the wall.A laser is sent down a UMD hallway in an experiment to corral light as it makes a 45-meters-long journey.

But for a handful of nights in 2021, UMD Physics Professor Howard Milchberg and his colleagues transformed the hallway into a laboratory: The shiny surfaces of the doors and a water fountain were covered to avoid potentially blinding reflections; connecting hallways were blocked off with signs, caution tape and special laser-absorbing black curtains; and scientific equipment and cables inhabited normally open walking space.

As members of the team went about their work, a snapping sound warned of the dangerously powerful path the laser blazed down the hall. Sometimes the beam’s journey ended at a white ceramic block, filling the air with louder pops and a metallic tang. Each night, a researcher sat alone at a computer in the adjacent lab with a walkie-talkie and performed requested adjustments to the laser.

Their efforts were to temporarily transfigure thin air into a fiber optic cable—or, more specifically, an air waveguide—that would guide light for tens of meters. Like one of the fiber optic internet cables that provide efficient highways for streams of optical data, an air waveguide prescribes a path for light. These air waveguides have many potential applications related to collecting or transmitting light, such as detecting light emitted by atmospheric pollution, long-range laser communication or even laser weaponry. With an air waveguide, there is no need to unspool solid cable and be concerned with the constraints of gravity; instead, the cable rapidly forms unsupported in the air. In a paper accepted for publication in the journal Physical Review XPhysical Review X the team described how they set a record by guiding light in 45-meter-long air waveguides and explained the physics behind their method.

The researchers conducted their record-setting atmospheric alchemy at night to avoid inconveniencing (or zapping) colleagues or unsuspecting students during the workday. They had to get their safety procedures approved before they could repurpose the hallway.

“It was a really unique experience,” says Andrew Goffin, a UMD electrical and computer engineering graduate student who worked on the project and is a lead author on the resulting journal article. “There's a lot of work that goes into shooting lasers outside the lab that you don't have to deal with when you're in the lab—like putting up curtains for eye safety. It was definitely tiring.”

Left to right Eric Rosenthal, a physicist at the U.S. Naval Research Laboratory; Anthony Valenzuela, a physicist at the U.S. Army Research Lab; and Goffin align optics at a porthole in the wall in order to send the laser beam from the lab down the hallway. The white dotted lines show the approximate beam path before and after the optics redirected it. All the work was to see to what lengths they could push the technique. Previously Milchberg’s lab demonstrated that a similar method worked for distances of less than a meter. But the researchers hit a roadblock in extending their experiments to tens of meters: Their lab is too small and moving the laser is impractical. Thus, a hole in the wall and a hallway becoming lab space.

“There were major challenges: the huge scale-up to 50 meters forced us to reconsider the fundamental physics of air waveguide generation, plus wanting to send a high-power laser down a 50-meter-long public hallway naturally triggers major safety issues,” Milchberg says. “Fortunately, we got excellent cooperation from both the physics and from the Maryland environmental safety office!”

Without fiber optic cables or waveguides, a light beam—whether from a laser or a flashlight—will continuously expand as it travels. If allowed to spread unchecked, a beam’s intensity can drop to un-useful levels. Whether you are trying to recreate a science fiction laser blaster or to detect pollutant levels in the atmosphere by pumping them full of energy with a laser and capturing the released light, it pays to ensure efficient, concentrated delivery of the light.

Milchberg’s potential solution to this challenge of keeping light confined is additional light—in the form of ultra-short laser pulses. This project built on previous work from 2014 in which his lab demonstrated that they could use such laser pulses to sculpt waveguides in the air.

The short pulse technique utilizes the ability of a laser to provide such a high intensity along a path, called a filament, that it creates a plasma—a phase of matter where electrons have been torn free from their atoms. This energetic path heats the air, so it expands and leaves a path of low-density air in the laser’s wake. This process resembles a tiny version of lighting and thunder where the lightning bolt’s energy turns the air into a plasma that explosively expands the air, creating the thunderclap; the popping sounds the researchers heard along the beam path were the tiny cousins of thunder.

But these low-density filament paths on their own weren’t what the team needed to guide a laser. The researchers wanted a high-density core (the same as internet fiber optic cables). So, they created an arrangement of multiple low-density tunnels that naturally diffuse and merge into a moat surrounding a denser core of unperturbed air.

The 2014 experiments used a set arrangement of just four laser filaments, but the new experiment took advantage of a novel laser setup that automatically scales up the number of filaments depending on the laser energy; the filaments naturally distribute themselves around a ring.

The researchers showed that the technique could extend the length of the air waveguide, increasing the power they could deliver to a target at the end of the hallway. At the conclusion of the laser’s journey, the waveguide had kept about 20% of the light that otherwise would have been lost from their target area. The distance was about 60 times farther than their record from previous experiments. The team’s calculations suggest that they are not yet near the theoretical limit of the technique, and they say that much higher guiding efficiencies should be easily achievable with the method in the future.

“If we had a longer hallway, our results show that we could have adjusted the laser for a longer waveguide,” says Andrew Tartaro, a UMD physics graduate student who worked on the project and is an author on the paper. “But we got our guide right for the hallway we have.”Distributions of the laser light collected after the hallway journey without a waveguide (left) and with a waveguide (right).

The researchers also did shorter eight-meter tests in the lab where they investigated the physics playing out in the process in more detail. For the shorter test they managed to deliver about 60% of the potentially lost light to their target.

The popping sound of the plasma formation was put to practical use in their tests. Besides being an indication of where the beam was, it also provided the researchers with data. They used a line of 64 microphones to measure the length of the waveguide and how strong the waveguide was along its length (more energy going into making the waveguide translates to a louder pop).

The team found that the waveguide lasted for just hundredths of a second before dissipating back into thin air. But that’s eons for the laser bursts the researchers were sending through it: Light can traverse more than 3,000 km in that time.

Based on what the researchers learned from their experiments and simulations, the team is planning experiments to further improve the length and efficiency of their air waveguides. They also plan to guide different colors of light and to investigate if a faster filament pulse repetition rate can produce a waveguide to channel a continuous high-power beam.

“Reaching the 50-meter scale for air waveguides literally blazes the path for even longer waveguides and many applications”, Milchberg says. “Based on new lasers we are soon to get, we have the recipe to extend our guides to one kilometer and beyond.”

Story by Bailey Bedford. Images by Intense Laser-Matter Interactions Lab, UMD.

In addition to Milchberg, Goffin and Tartaro, Aaron Schweinsburg and Anthony Valenzuela from the DEVCOM Army Research Lab, and Eric Rosenthal from the Naval Research Lab are also authors and Ilia Larkin, a former UMD graduate student and current systems engineer at KLA, is a co-lead author.

Publication information: https://journals.aps.org/prx/accepted/8707dK4dIb91a60bb6df4e56bdc44a53b2267be80

PI affiliations: Howard Milchberg is jointly appointed to the departments of Physics and Electrical and Computer Engineering and is affiliated with the Institute for Research in Electronics and Applied Physics.

This work is supported by the Office of Naval Research (N00014-17-1-2705 and N00014-20-1-2233), the Air Force Office of Scientific Research and the JTO (FA9550-16-1-0121, FA9550-16-1-0284, and FA9550-21-1-0405), the  Army Research Lab (W911NF1620233) and the Army Research Office (W911NF-14-1-0372).

Jonathan D. Moreno,  the David and Lyn Silfen University Professor at the University of Pennsylvania, gave the third Irving and Renee Milchberg Endowed Lecture on Tuesday, April 4, 2023.

Moreno's talk addressed Bioethics and the Rules-Based International Order.   Jonathan Moreno. Credit: University of Pennsylvania

Moreno, an elected member of the National Academy of Medicine, studies medical ethics and health policy, the history and sociology of science, and philosophy. He received  his Ph.D. in philosophy from Washington University in St. Louis and was an Andrew W. Mellon post-doctoral fellow. His book The Body Politic: The Battle Over Science in America was a Kirkus Reviews Best Book of the Year and a Scientific American Book Club selection. More recently, he wrote Everybody Wants to Go to Heaven but Nobody Wants to Die: Bioethics and the Transformation of Healthcare in America with former Penn President Amy Gutmann.

Moreno received the 2018 Lifetime Achievement Award of the American Society for Bioethics and Humanities. 

The Irving and Renee Milchberg Endowed Lectureship was established by Prof. Howard Milchberg and his wife Rena, to remember Howard's parents, who survived the Holocaust and the distortions of truth that accompanied and facilitated it.  Milchberg’s mother and father, who died in 2017 and 2014, respectively, never received formal education, but Milchberg describes them as “remarkably open-minded and tolerant” and as “wide-ranging thinkers and skeptics.”