Stark-Shift AoA Sensing
Phase-independent angle-of-arrival estimation from Stark-shifted Rydberg-EIT spectra measured at a single spatial location.
RF • Microwave • Quantum Sensing
Rajavardhan Talashila (RT)
RF & Microwave Engineer working at the intersection of electromagnetics and Rydberg-atom sensing
I develop RF sensing techniques using Rydberg atoms while drawing on a background in antennas, microwave engineering, electromagnetic simulation, and wireless systems. My path spans telecommunications, antenna and electromagnetic research, 5G RF hardware, HFSS-based engineering at Ansys, and now Rydberg-atom RF sensing at NIST.
Professional & Research Profiles
Research Highlights
Floquet Avoided Crossings
Floquet/Shirley interpretation of avoided crossings, RF-dressed states, replicas, and multiphoton coupling pathways in Rydberg-EIT spectra.
Amplitude-Only AoA Estimation
Compact direction finding from subwavelength standing-wave measurements in a Rydberg-atom sensor without a conventional phase-resolved antenna array.
Current Research Focus
Rydberg RF Sensing & Direction Finding
Developing compact Rydberg-atom RF sensors for electric-field measurement and angle-of-arrival estimation, including subwavelength standing-wave, fluorescence-imaging, and Stark-spectroscopic approaches.
Floquet Spectroscopy & Avoided Crossings
Studying AC Stark shifts, Autler-Townes structure, arbitrary RF polarization, Floquet replicas, multiphoton coupling pathways, and avoided crossings that govern the response of Rydberg-EIT sensors.
Sensitivity, Dynamic Range & Nonlinear Response
Characterizing calibrated electric-field response across VHF, UHF, and microwave frequencies, with emphasis on sensitivity, dynamic range, heterodyne beat-note detection, intermodulation, and signal fidelity.
Professional Experience
Project Associate — NIST
Conducting experimental and theoretical research in Rydberg-atom RF sensing, spanning direction finding, RF electrometry, RF-dressed spectroscopy, Floquet modeling, and automated RF/optical measurements.
Senior Application Engineer — Ansys
Supported engineering teams across antennas, PCBs, sensing devices, EMI/EMC, signal integrity, power integrity, and radiation problems using HFSS and related simulation tools.
Contributed to digital beamforming-array simulation work associated with AFRL.
Project Assistant — 5G Testbed, IIT Madras
Designed, fabricated, and experimentally tested a 3.5 GHz passive bandpass filter and contributed to antenna design and testing for 5G base-station applications.
Junior Telecom Officer — BSNL
Worked with wired telephony, 2G/3G cellular systems, optical-fiber networks, and customer-facing telecommunications operations.
Selected Engineering Projects
Digital Beamforming System Simulation
Contributed to system-level simulation of digital beamforming arrays using Ansys HFSS, Keysight PathWave SystemVue, and AGI/STK, combining electromagnetic models with RF-system and platform-level behavior.
3.5 GHz Bandpass Filter
Designed, fabricated, and experimentally validated a passive 3.5 GHz bandpass filter for the IIT Madras 5G Testbed.
Antenna, Polarization & Link Analysis
Analyzed spacecraft attitude, antenna radiation patterns, LHCP/RHCP polarization, orbital visibility, and link budgets for a LEO satellite communication system.
Multipole Expansion of Antenna Radiation
Developed and studied multipole and spherical-harmonic representations of radiation from wire, patch, and horn antennas, with results published in IEEE Antennas and Wireless Propagation Letters.
Selected Publications
Talashila, R., Popovic, Z., Prajapati, N., Schlossberger, N., & Holloway, C. L. (2026).
“Angle-of-Arrival Determination of Radio-Frequency Fields Using Stark-Shifted Rydberg-EIT Spectra.”
arXiv preprint, arXiv:2609.17459.
arXiv →
Focus: phase-independent AoA estimation from angle-dependent amplitudes of AC Stark-shifted Rydberg-EIT magnetic-sublevel resonances at a single spatial location.
Focus: phase-independent AoA estimation from angle-dependent amplitudes of AC Stark-shifted Rydberg-EIT magnetic-sublevel resonances at a single spatial location.
Talashila, R. et al. (2026).
“Floquet Interpretation of Avoided Crossings in AC Stark-Shifted Rydberg-EIT Spectra.”
arXiv preprint, arXiv:2609.06062.
arXiv →
Focus: Floquet interpretation of avoided crossings and RF-dressed spectral structure in AC Stark-shifted Rydberg-EIT.
Focus: Floquet interpretation of avoided crossings and RF-dressed spectral structure in AC Stark-shifted Rydberg-EIT.
Schlossberger, N., Talashila, R., Oliver, S. B., Prajapati, N., Watterson, W. J., & Holloway, C. L. (2026).
“Resolving magnetic-sublevel structure in Rydberg Autler-Townes spectra with arbitrary rf polarization.”
Physical Review A, 114, 033701.
DOI →
Focus: polarization-dependent Rydberg Autler-Townes spectra and magnetic-sublevel structure for RF electrometry and polarimetry.
Focus: polarization-dependent Rydberg Autler-Townes spectra and magnetic-sublevel structure for RF electrometry and polarimetry.
Schlossberger, N., Talashila, R., Prajapati, N., & Holloway, C. L. (2025).
“Angle-of-arrival detection of radio-frequency waves via Rydberg-atom fluorescence imaging of standing waves in a glass vapor cell.”
Physical Review Applied, 24, 024056.
DOI →
Focus: 37-GHz angle-of-arrival detection using spatially resolved Rydberg fluorescence imaging of standing waves in a compact glass vapor cell.
Focus: 37-GHz angle-of-arrival detection using spatially resolved Rydberg fluorescence imaging of standing waves in a compact glass vapor cell.
Talashila, R., Watterson, W. J., Moser, B. L., et al. (2025).
“Determining Angle of Arrival of Radio-Frequency Fields Using Subwavelength, Amplitude-Only Measurements of Standing Waves in a Rydberg Atom Sensor.”
Journal of Applied Physics, 138(11), 114402.
DOI →
Focus: compact Rydberg-atom direction finding using subwavelength field measurements.
Focus: compact Rydberg-atom direction finding using subwavelength field measurements.
Talashila, R., & Ramachandran, H. (2021).
“Effect of polarization on the link dynamics of a spinning low-earth orbit satellite aligned with geomagnetic field.”
Engineering Reports.
Open access →
Talashila, R., & Ramachandran, H. (2020).
“Multipole Expansion of Radiation From Patch Antenna Using Quasi-Static Surface Currents.”
IEEE Antennas and Wireless Propagation Letters, 19(12), 2136–2140.
IEEE Xplore →
Talashila, R., & Ramachandran, H. (2019).
“Determination of Far Fields of Wire Antennas on a PEC Sphere Using Spherical Harmonic Expansion.”
IEEE Antennas and Wireless Propagation Letters, 18(4), 646–650.
IEEE Xplore →
Patents & Inventions
2D electromagnetic field imager using light-sheet fluorescence spectroscopy of Rydberg states
A Rydberg-atom field-imaging approach that combines light-sheet excitation and fluorescence imaging to map electromagnetic fields over a two-dimensional region.
Rydberg Electrode Cell Angle of Arrival Estimator
A compact angle-of-arrival sensing concept that uses subwavelength standing-wave structure inside a Rydberg vapor-cell system to estimate incoming RF direction from amplitude measurements.
Technical Skills
RF & ElectromagneticsAntennas, RF & microwave engineering, EMI/EMC, signal integrity, power integrity, wireless systems, electromagnetic modeling
Simulation & Engineering SoftwareAnsys HFSS, Ansys SIwave, CST Microwave Studio, Keysight PathWave SystemVue, AGI/STK, LabVIEW
RF Measurements & InstrumentationVector network analyzers, spectrum analyzers, oscilloscopes, signal generators, LCR meters, laboratory data acquisition
Quantum / Atomic RF SensingRydberg atoms, EIT spectroscopy, RF electrometry, AC Stark effects, atom-based field sensing, Floquet/Shirley methods
ProgrammingPython, MATLAB, Fortran, CUDA Fortran
Experimental ResearchRF/optical laboratory automation, spectroscopy, signal analysis, model-to-measurement validation
Technical Reference Material
Electromagnetics & RF Reference Notes
A growing collection of technical reference material covering electromagnetics, antennas, RF and microwave systems, computational methods, sensing, quantum-enabled RF concepts, and engineering applications. The notes are developed with AI-assisted drafting and my own organization and technical review.
Explore EM Notes →Simulation demonstrations
Education
Ph.D., Electrical Engineering — Quantum Sensing
Expected 2026 • GPA 3.83/4.00
M.S., Electrical Engineering
2025 • GPA 3.83/4.00
Ph.D., Electrical Engineering — RF & Microwave
2021 • CGPA 8.34/10
M.Tech., Electrical Engineering — Photonics
2021 • CGPA 8.34/10
Reading
I read broadly across physics, science, history, philosophy, and literature, and keep a separate page as a personal record of books and ideas worth revisiting.
Explore my reading list →Let’s Connect
I am interested in research and engineering opportunities involving RF and microwave systems, antennas, electromagnetic simulation, advanced RF measurements, wireless systems, and quantum-enabled sensing.
trvabc@gmail.com · Resume · LinkedIn · Google Scholar · Web of Science · ORCID · YouTube