👋🏼 Welcome, I’m Jiachen He!

Faraday Lab overlook — *Take a look at where I work.*

👨‍💻 Final-year Ph.D. candidate in physics at the University of Kentucky, specializing in open quantum systems, optical metrology, and magnetic field design.

⚛️ Engaged in research on optical and magnetic systems, with a focus on the magneto-optic effect, laser frequency stabilization, advanced data acquisition / analysis techniques, and the development of high-precision instrumentation.

🎓 Currently working on a Ph.D. dissertation that involves developing a sensitive optical magnetometer based on the resonant nonlinear Faraday effect. Additionally, extensive work has been done on laser frequency stabilization, Python-based systems for synchronous data acquisition and designing a Merritt coil system to generate compact uniform magnetic field.

🎯 Driven by a passion for optics, quantum technology, and engineering expertise to streamline scientific workflows. Proficient in Python, C++, and a suite of tools, applying them to innovate across hardware and software development while pushing the boundaries of experimental precision.

About the Faraday Lab

📽️ Click here if you want to learn more about the Faraday Lab.

Selected Experience

🔧 Scientific Software Development

Strong background in object-orientated programming, personally developed and maintained several Python packages that contribute to scientific research, including:

Faraday_DA: A tool for analyzing rotation measurements with a focus on script automation, supporting Faraday rotation measurements.
Faraday_DAQ: A modular system that facilitates seamless communication between scientific instruments, such as wavelengthmeter, Gaussmeter, laser controller, and lock-in amplifiers using Python.

You can explore all my software contributions on my GitHub profile, where I promote transparency and collaboration in scientific research.

🌀 Optical Metrology

Expert in polarization modulation ellipsomtry, with particular emphasis on system setup, calibration, and optimization. Developed a system for detecting minute magnetic field variations associated with spin-polarized Helium-3 targets using magneto-optic effects without magnetic shielding, estimating a shot noise limited sensitivity of $4.8\times10^{-11}\,\text{G}/\sqrt{\text{Hz}}$ under spin-exchange optical pumping operating temperautre ($\sim510\ \text{K}$).

🔦 Laser Frequency Stabilization

Extensive experience in laser locking, employing advanced techniques such as Pound-Drever-Hall locking and Doppler-free saturated absorption spectroscopy, integrating complex optical systems and electro-optical devices to achieve high-precision frequency control.

Merrit coil system — *Compact magnetic field design and engineering.*

🧲 Magnetic Field Design

Designed and developed a Merritt coil system for generating uniform magnetic fields, utilizing Python and finite element analysis (COMSOL).
Collaborated closely with machine shop teams to build and test the system, which plays a critical role in my research on active magnetic field cancellation.

🧊 Cryogenic and Vacuum Systems

Contributed to system calibration and maintenance of a cryogenic system, gaining hands-on experience with vacuum technologies over five years.

🖥️ Professional Experience

As a Graduate Research Assistant at the University of Kentucky, I have led and contributed to numerous research projects focused on precision metrology, polarization modulation, and magnetic field optimization. I have worked closely with cross-functional teams to design and implement custom experimental setups using state-of-the-art optical and laser technologies.

🧑‍🏫 Collaboration & Leadership

I am passionate about fostering the next generation of scientists and engineers through mentorship and collaboration:

Undergraduate Mentorship: Supervised multiple undergraduate students during the Research Experiences for Undergraduates (REU) program, including one from MIT, providing theoretical guidance on the resonant Faraday effect in a two-level system. This work culminated in a presentation at the 2024 Division of Nuclear Physics (DNP) Meeting.
High School Mentorship: Guided a high school student through a scientific project to explore the polarization of light and measure the speed of light using cavity mirrors and a rotating mirror.
Community Engagement: Previously served as the representative of the Physics Department in the University of Kentucky Graduate Student Congress (GSC) and was appointed as the Department of Physics & Astronomy Alumni Liaison, a role in which I am honored to serve.

Chem-Phys Bldg, University of Kentucky — *My favorite view of the Chem-Phys Bldg at University of Kentucky.*

📚 Education

Ph.D. in Physics, University of Kentucky (Expected Graduation: May 2025)
M.S. in Physics, University of Kentucky
B.E. in Measurement Control Technology and Instruments (equivalent to EE), Shenzhen University

📜 Publications and Presentations

Electric Charging Effects on Insulating Surfaces in Cryogenic Liquids, Review of Scientific Instruments.
Using the Resonant Faraday Effect to Probe External Magnetic Fields, presented at the American Physical Society Global Physics Summit, 2025.
Faraday Rotation Measurements in a Potassium Vapor Cell, presented at the American Physical Society April Meeting, 2024.

🤝 Looking for Collaborations?

I am always eager to explore new research collaborations and share knowledge in fields such as optics, laser technology, magnetic systems, quantum technology and scientific computing.

Feel free to browse my repositories and reach out to me for potential collaborations or discussions on scientific software development.

👨‍💻 Connect with me: