Meet the 2025 Truman and Hruby Fellows

Distinguished Level Fellowships are three-year appointments that allow individuals to advance Sandia’s national security mission, conduct in-depth research at state-of-the-art facilities and learn from recognized engineers and scientists.

The 2025 Hruby Fellows are Ravyn Malatesta and Olivia Krohn, and the 2025 Truman Fellows are Dan Herman and Sam Peana.

Hruby Fellow Ravyn Malatesta

The Jill Hruby Postdoctoral Fellowship stands out for its dual focus on scientific inquiry and leadership development. For many, including Ravyn Malatesta, this fellowship represents an opportunity to blend intellectual freedom with the chance to cultivate essential leadership skills.

“I was particularly drawn to the Jill Hruby Fellowship because of its focus on both scientific research and scientific leadership,” she said. “It offers a lot of freedom to direct your own research in an environment equipped with the facilities and technical expertise to support bold and ambitious science.”

The road from chemistry to physics

Ravyn’s journey to physics was not a straightforward path. “I like to say that I took a sort of ‘back door’ into physics,” she said. Initially rooted in chemistry, her fascination with quantum mechanics blossomed through quantum chemistry. As she delved deeper into research, she recognized her interests aligned more closely with physics.

Now, as a fellow, Ravyn is focusing on the intricate relationship between light and matter, particularly how entanglement and other quantum properties of photons change when interacting with materials. Her current research explores the use of advanced materials, specifically metasurfaces, ultrathin films that support arrays of artificial nanostructures, to generate and control hyperentangled photon states. This approach could significantly enhance the information-carrying capacity of entangled photon signals, making them more resilient to noise and beneficial for quantum communication and applications in low signal-to-noise environments, such as imaging and sensing.

Despite the groundbreaking nature of her work, Ravyn remains grounded in her motivations. “To be honest, as a researcher, I’m not particularly motivated by research prestige or renown,” she said. “I’m interested in doing good, fundamental research that is respected and that I find interesting.”

She aspires not to be the next world-changing inventor but to contribute to a field that is rapidly advancing, often referred to as the “second quantum revolution.”

Improving science communication

During her doctorate program, Ravyn participated in leadership initiatives aimed at community building and enhancing science communication.

Looking ahead, Ravyn envisions a career dedicated to elevating the standards of scientific communication. “A good scientist must be able to communicate their science effectively, but effective scientific communication is more or less an afterthought in most scientific education and training,” she said. She believes that advocating for improved communication standards at all levels will lead to more effective interdisciplinary collaboration, greater public trust and, ultimately, better science.

As Ravyn embarks on a new chapter of her career through the Jill Hruby fellowship, she exemplifies the potential of combining scientific inquiry with leadership, paving the way for future advancements in both research and communication in the scientific community.

Hruby Fellow Olivia Krohn

In chemical physics, understanding molecular interactions is vital for scientific advancement. Olivia Krohn, a Jill Hruby Fellow, is investigating these interactions at low energies, which could revolutionize understanding of chemical processes and lead to innovative technologies.

The nature and importance of molecular collisions

“My research dives into how molecules interact with each other, especially when they’re moving slowly,” she said. “When two atoms collide, their behavior isn’t so different from tiny billiard balls. However, molecules have shapes and additional motions like rotations and vibrations, which require energy. When two molecules collide, they redistribute that energy in interesting ways that are hard to predict.”

Studying these energy transfers is essential for testing the accuracy of theoretical predictions about molecular interactions. While complex theories exist to predict molecular behavior, they often fall short, particularly with larger or more energetic molecules. This is where experimental research becomes invaluable.

“Direct measurements can check and improve our theories, which is important for understanding collisions and chemistry in all kinds of environments, such as the atmosphere, space, engines and more,” she said.

Olivia’s lab work involves advanced techniques, such as using lasers. “Lasers are powerful tools in chemical physics, capable of influencing and detecting energy distribution in molecules,” she said. One significant use is tracing energy flow during chemical processes. The research team employs lasers to measure energy distribution post-collision. By using a laser that can ionize an electron only in a specific energy state, they create more readily detectable charged particles. This method, known as velocity map ion imaging, enables researchers to assess the velocity of molecules after collisions.

Studying larger molecular systems has traditionally been challenging due to difficulties in controlling initial velocities. However, Olivia’s team has developed a novel method to narrow velocity spreads using lasers. All lasers have a spread of wavelengths or colors associated with them; this is called the “linewidth” of the laser. By exciting target molecules with very narrow linewidth lasers, they can manipulate the speeds of these excited molecules through a clever use of the Doppler effect. This also allows excellent control of the rotation and vibration of the molecules, which yields more information in the collision studies.

“This new approach excites me because it allows us to study more complex systems than ever before,” she said.

Motivation for pursuing the Jill Hruby Fellowship

Olivia was drawn to the Jill Hruby Fellowship because it’s a rare opportunity to engage in cutting-edge research while being part of a collaborative and innovative community. “The fellowship aligns perfectly with my passion for exploring molecular interactions and provides access to resources and mentorship that are crucial for my development as a scientist,” she said. “Being part of a program that honors a pioneering woman in science inspires me to push the boundaries of what we know and to contribute to the next generation of scientific breakthroughs.”

The implications of this research extend beyond the lab. By deepening understanding of molecular interactions, Olivia’s work could enhance precision models for high-energy environments like lightning storms and explosions, interpret light emissions from cooler settings such as space or atmospheric chemistry, or improve energy efficiency in various processes.

Ultimately, the goal is to grasp these interactions fundamentally, paving the way for their control. “Imagine steering a chemical reaction to produce exactly what we want,” Olivia said.

Truman Fellow Dan Herman

Truman Fellow Dan Herman knows a thing or two about optical frequency combs, special lasers that emit a spectrum of colors simultaneously in the form of ultra-short optical pulses, bridging the gap between high optical frequencies, terahertz to petahertz, and lower radio frequencies, megahertz to gigahertz. Originally designed to connect optical atomic clocks to standard electronics, frequency combs have found applications in various fields, including trace gas sensing, optical communications, optical time transfer and atomic cooling.

The impact of optical frequency combs on scientific research

For Dan, the world of optical frequency combs is not just about advancing technology; it’s about making a tangible impact on scientific processes.

“For my Truman research, I will be developing combs into remote gas sensors for understanding ecological processes,” he said. “I will also be developing systems for high-speed spectroscopy in laboratory environments and quantum sensing applications of frequency combs.”

This innovative technology plays a crucial role in helping us understand the chemical properties of the air we breathe.

During his doctorate program at the National Institute of Standards and Technology, Dan collaborated with agronomists and soil scientists from Kansas State University to develop a better on-site method for measuring gas emissions from cattle farms. “This collaboration yielded a method that can accurately track methane and ammonia flux from farms with minimal external calibration,” he said. The resulting technology is now used to better understand emissions from grazing animals, an area that has not been well characterized until now.

Dan’s experiences have shaped his perspective on the importance of scientific research. “While my own research touches on both fundamental and applied advances, I believe that the most important science will always keep the human experience in mind,” he said.

His commitment to advancing atmospheric remote sensing stems from a desire to enhance public health and quality of life. “I believe these advancements will help everyone lead healthier, happier lives,” he said. “I feel fortunate to have a career that allows me to study the fundamental nature of matter and light while applying these insights to improve our well-being.”

Pursuing a Truman Fellowship

Dan’s decision to pursue the Truman Fellowship was driven by his desire to bridge the gap between advanced scientific research and real-world applications that benefit society.

“The Truman Fellowship represents an opportunity to not only advance my research in optical frequency combs but also to engage with a community of like-minded individuals who are committed to making a difference,” he said. “I chose this fellowship because it aligns perfectly with my goal of leveraging technology to address pressing environmental and health issues.”

The fellowship provides a platform for Dan to collaborate with experts across various disciplines. “Being part of the fellowship community allows me to connect with other researchers who share my passion for impactful science,” he said. “Together, we can tackle complex challenges and drive meaningful change.”

Through the Truman Fellowship, Dan aims to amplify the impact of his work on ecological processes and public health, reinforcing his belief that scientific advancements should ultimately serve humanity.

Truman Fellow Sam Peana

As a child, Truman Fellow Sam Peana’s curiosity ignited a lifelong passion for technology. At age 11, he realized that computers had to be instructed what to do, leading him to his father’s book on the programming language titled “Visual Basic.” With the Visual Basic 1.0 floppy disk in hand, he began his lifelong journey into programming and engineering.

A year later, his father gifted him a Parallax Propeller microcontroller, further fueling his interest. “My father chose the Propeller because he thought I would get bored with the Basic Stamp,” Sam said. The sparse documentation of the Propeller, designed for professional engineers, encouraged him to explore independently, leading to projects such as an eight-channel music synthesizer and a simple robot. These experiences taught him that science and engineering are grand adventures — a philosophy that continues to guide his work today.

The promise of quantum photonics

Sam’s latest adventure is his current work in quantum photonics. During his doctorate, he was part of a team that discovered a new type of single-photon emitter occurring in silicon nitride-oxide, which promises to be crucial for a variety of quantum optical applications.

“Single-photon emitters produce one photon at a time, essential for quantum optical applications such as computing, networking and sensing,” he said. In addition to being one of the co-discoverers of this type of emitter, Sam, discovered a method to produce these emitters at specified locations using methods compatible with standard semiconductor manufacturing techniques. This means that standard foundries, such as the Microsystems Engineering, Science and Applications complex, could potentially produce quantum optical devices at wafer scale, like current microchips. This would be a game changer in practical quantum devices. His current research is to understand and optimize this process to make it useful for applications.

Quantum devices and experiments have demonstrated a variety of useful applications from ultra-high-performance sensors, quantum secure networking and quantum information processing. However, many of these applications are still only lab-scale demonstrations; large-scale manufacturing is the next key step to take these devices from the lab to everyday users.

Advice for aspiring scientists and engineers

Emphasizing perseverance and hard work, Sam recalls a five-year struggle to make a previous project on micro-robotics with shape-memory alloys successful. This effort ultimately and unexpectedly led to success with single-photon emitters.

His advice to aspiring scientists and engineers is to “be audacious. You miss every ball you don’t swing at. Don’t limit yourself by thinking you aren’t good enough or that you won’t succeed.”