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Physics senior Ruijian Wang has been awarded the Fall 2025 Stephen Halley White Undergraduate Research Award from the Department of Physics for his outstanding research in quantum optics and integrated photonics. The award is one of the top honors for graduating physics students at CU ��������.

Established in 2013 by alumnus Dr. Stephen White (Phys’63), the award recognizes exceptional undergraduate research projects. During his undergraduate studies at CU ��������, Dr. White held several research positions which made an impact on his career and led him to create this award.

A passion for physics

Wang said his interest in physics stemmed from a fascination with math, and how scientists can use a few elegant equations to ��describe the fundamental physical principles of our universe. He spent several years studying physics, math and music in China before continuing his studies in the United States.��

He pursued his interest in Atomic, Molecular, and Optical (AMO) physics through research positions at Yale University and at MIT. As the first undergraduate student to work in at Yale University, he designed and improved PID feedback control circuits for advanced quantum simulation experiments with quasicrystals. Later, as a visiting student at MIT’s physics department from 2023 to 2024, he worked with Prof. Ronald Fernando Garcia Ruiz and led the design, implementation, and optimization of an off-center rotating Ablation Ion Source for laser spectroscopy experiments.��

After these experiences, Wang considered where to finish his bachelor’s degree, and �������� was strongly recommended as a top choice.

Squeezed light on a chip

After transferring to CU ��������, Wang started looking for a research group where he could enhance his hands-on skills with optics.��

“I was very interested in Professor Scott Diddams’ leading work in frequency comb and quantum metrology, so I stopped by his office and asked for one minute to introduce myself. He said he had five minutes to talk before his next meeting,” said Wang. Nothing like a time crunch to make a good first impression – Wang quickly explained his interests and to his surprise, Diddams said he might have an opening on a new project.

His project in quantum optics and integrated photonics involved making a special quantum state of light, called a squeezed state, on a tiny photonic chip about half the size of a penny. This special state reduces uncertainty in one physical quadrature of a quantum system and is key to improving precision measurements and quantum metrology.��

Wang suddenly had a lot of studying to do. At first, they didn’t have their own experimental table, so he began pouring over research papers on the topic. He and Diddams started building the experiment setup from an empty table and Wang said that experience gave him extensive training, both in designing and setting up the experiment and in purchasing and working with vendors.��

“One of the most unique things I learned was not just the individual experimental techniques, but how to plan and execute a project in its entirety,” said Wang. He noted that the real-world experience combined with weekly collaboration review meetings have set him up well for his future research career.��

“Ruijian is an exceptional undergraduate researcher with amazing drive and curiosity-driven motivation for learning,” said Diddams, Wang’s research advisor and professor of electrical, computer and energy engineering and physics. “Usually, the generation of squeezed light requires a full table of equipment, but Ruijian is showing how to do that using a small photonic chip that could ultimately fit on the tip of your finger.”��

This experiment is the “first step towards a robust and scalable approach of on-chip squeezed-light sensors for a new class of integrated photonics sensors,” Wang described in his honors thesis.

Earning top honors

Wang received a summa cum laude designation from the College of Arts & Sciences Honors Program for writing and defending his undergraduate thesis. The Physics Honors Council Representatives then selected him to receive the Stephen Halley White Undergraduate Research Award.

Jun Ye, professor adjoint of physics and JILA fellow, served as the Physics Honors Council Representative on Wang’s defense. “I was very impressed with the scientific knowledge and technical depth that Ruijian demonstrated through his written thesis and verbal presentation,” said Ye.��

Upon earning the research award, Wang said he was proud to receive recognition from the Honors Council Representatives and the Department of Physics.��

“It was great to hear the faculty who served on my defense were interested in what we’re doing in the lab, both the science and application aspects. It was nice recognition,” said Wang. “I really appreciate the honor and it’s good encouragement for the future.”

What’s next?

After graduating this fall, Wang plans to continue working in Diddams’ lab as a researcher. As the first college student in his family, he’s currently applying for graduate school, planning to pursue a Ph.D. in physics next fall. He believes the most important aspect of higher education was that it gave him the opportunity to explore different career paths.

Wang also earned the Jennifer Turner-Valle Scholars Fellowship and an SPIE Fellowship from CU’s Quantum Scholars program. He said the program gave him great insight into the quantum industry, and he wants to continue conducting research to develop quantum technologies for real-world applications.

“As a part of the quantum community, I want to help develop the next generation of AMO techniques for both fundamental physics exploration and impactful applications outside physics labs,” said Wang.��