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The Britton Trapped Ion Lab is a joint effort between the DEVCOM Army Research Laboratory (ARL) and the University of Maryland in College Park. Our work on quantum networking and sensing with trapped ions takes place on the campus of the University of Maryland.
News
BIFROST
BIFROST
Patrick Banner published BIFROST, a first-principles model of polarization mode dispersion (PMD) in optical fibers. Unlike conventional models, BIFROST employs physically motivated representations of the PMD properties of fibers, allowing users to computationally investigate real-world fibers in ways that are connected to physical parameters such as environmental temperature and external stresses. Our model, implemented in an open-source Python module, incorporates birefringence from core geometry, material properties, environmental stress, and fiber spinning. BIFROST's physical grounding enables investigations into such questions as the sensitivity of fiber sensors, the evaluation of PMD mitigation strategies in quantum networks, and many more applications across fiber technologies. [github] [arXiv]
A forthcoming update will refactor the codebase for improved speed and modularity. Please be in touch with questions or ideas for extensions of the codebase.
12/2025
On PDH Offset Errors
On PDH Offset Errors
Here we report on a routinely underestimated source of error in PDH offset-locking: a shift in the lock point due to the unintended interaction between residual optical sidebands and higher-order spatial modes in misaligned Fabry-Pérot cavities. Significant frequency deviations—up to 50% of the cavity linewidth—can arise when the optical offset is obtained from a sinusoidally driven EOM.
See Hildebrand, et al "Errors in PDH Offset Locking due to Spurious Spectral Features" in Optics Express. [pdf] [arXiv:2412.05411]
11/2025
Mitigating Charging of Mirrors
& Cavity–Metalens–Fiber Assembly
Mitigating Charging of Mirrors
& Cavity–Metalens–Fiber Assembly
Wance Wang posted two preprints.
"Can TCOs Transform Cavity-QED?" [arXiv:2506.02501]
"Cavity–Metalens–Fiber Assembly for Mode Matching: Tolerance Analysis and Experimental Implementation" [arXiv:2506.03626]
6/2025
Serrodyne Offset Locking
Serrodyne Offset Locking
Roame Hildebrand published "Spectrally-Pure Optical Serrodyne Modulation for Continuously-Tunable Laser Offset Locking" in Optics Express. He shows record-setting high-bandwidth CW optical frequency offsetting using the serrodyne technique. This is relevant to precision atomic spectroscopy. [arxiv] [pdf]
6/2025
BA High Honors
BA High Honors
Recently Roame Hildebrand presented his senior thesis titled "Optical Serrodyne Modulation for Continuously-Tunable Laser Offset Locking." Today UMD Physics recommended him for a B.A. with High Honors in light of the excellence of his research. Congratulations Roame!
Following graduation Roame is doing a gap year in the Heinzen Lab at UT Austin (link).
4/29/2025
Rydberg RA
Rydberg RA
The Rydberg sensing team has an RA opportunity available to current and incoming UMD graduate students for Autumn 2025. You can read about the work taking place in this lab in partnership with Nathan Shine (JQI) in the attached posters.
on applied sensing, Josh Hill (link)
on fundamental studies & RydIQule software package, Kevin Cox (link)
Contact Dr Britton or the point of contact listed on the posters for more information.
4/10/2025
Trapped Ion RA
Trapped Ion RA
The Britton Lab has an RA opportunity available to current and incoming UMD graduate students for Autumn 2025. Open projects include modeling polarization mode dispersion for polarization-encoded photonic qubits, building the next generation cryogenic ion-cavity system and modeling ring-shaped ion traps for quantum computing. Contact Dr Britton for more information.
4/10/2025
NIST Quantum Optics Seminar
NIST Quantum Optics Seminar
Patrick Banner presented at the NIST Quantum Optics Seminar about his software package BIFROST (github), a first-principles model of polarization dynamics in optical fibers for quantum networking.
Abstract: A new generation of quantum networks is beginning to come online, evaluating questions of efficiency and practicality is becoming critical to the continued growth of these networks. Polarization qubits suffer from polarization mode dispersion (PMD) effects as they traverse long optical fibers, and these PMD effects are random and time-varying, making compensation a challenge. In this talk we present BIFROST, a Python-based simulation tool for describing and understanding PMD in optical fibers. The models BIFROST implements are based in first-principles physics rather than observed statistics, allowing for intuition behind PMD effects, and has been validated against experimental observations in spooled, aerial, and buried fibers. As an example, we describe computational results regarding wavelength-division multiplexing compensation schemes.
4/1/2025
Goldwater Scholar
Goldwater Scholar
Congratulations to Pranav Mathur (Princeton) who won a 2025 Barry Goldwater Scholarship. Pranav worked in the group from 2022-2024 and is now advised by James Thompson and Nathalie de Leon (Princeton).
3/28/2025
University Medal Nomination
University Medal Nomination
Group member Roame Hildebrand was nominated for the 2025 University Medal Award. "The University of Maryland's University Medal is the highest honor bestowed upon a graduating senior. It recognizes a student who exemplifies academic distinction, extraordinary character, and significant extracurricular contributions to both the university and the broader community." Good luck Roame!
2/27/2025
Quantum Network Town Hall
Quantum Network Town Hall
Patrick Banner presented a poster in NYC at the Quantum Network Town Hall event organized by SUNY and the NSF. The poster is on an open source Python library that implements a first-principles model of polarization mode dispersion in optical fibers (BIFROST). A rough draft of the library is available on github.
2/29/2025
Berkeley Seminar
Berkeley Seminar
2025 NACTI
2025 NACTI
Several group members presented at NACTI 2025 at UCLA.
Andrew Laugharn on "Low Vibration Closed-Cycle Flow Cryostat for Ion-Cavity Experiments" (link)
Connor Goham on "Towards direct telecom wavelength ion-photon entanglement with trapped Yb+" (link)
Wance Wang on "A cryogenic optical cavity for Yb+ quantum networking" (link)
Roame Hildebrand on "Spectrally-Pure Optical Serrodyne Modulation for Laser Offset Locking" (link)
8/14/2024
B.A. defense
B.A. defense
Evan McClintock successfully defended his UMD physics senior thesis research on the topic "Polarization Drift in Buried Fiber Optic Cables."
5/30/2024
Goldwater Scholar
Goldwater Scholar
Congratulations to Deven Bowman who won a 2023 Barry Goldwater Scholarship. Deven worked in the Rolston, Porto and Britton labs on optical polarimeters 2022-2023.
4/7/2023
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