RF • Microwave • Quantum Sensing

Rajavardhan Talashila (RT)

RF & Microwave Engineer | Rydberg RF Sensing | Antennas & Electromagnetics | Wireless Systems

I work at the intersection of RF and microwave engineering, electromagnetics, wireless systems, and quantum-enabled sensing. My current research at NIST explores how Rydberg atoms can be used as compact RF sensors for direction finding, electric-field measurement, and spectroscopy of RF-dressed atomic states.

RF & Microwave Antennas HFSS / CST EMI / EMC Wireless Systems Rydberg RF Sensing RF Measurements

Professional & Research Profiles

Resume LinkedIn Google Scholar Web of Science ORCID

Current Research Focus

NIST • Boulder, Colorado

Rydberg-Atom RF Sensing & RF-Dressed Spectroscopy

My research combines RF engineering, atomic spectroscopy, electromagnetic modeling, signal analysis, and automated instrumentation. Two connected themes run through this work: developing compact Rydberg-atom RF sensors, and understanding the RF-dressed atomic physics that governs their response.

  • RF direction finding: developing complementary AoA architectures based on subwavelength standing-wave measurements, spatial fluorescence imaging, and single-location Stark-spectroscopic sensing.
  • Broadband RF sensing: characterizing Rydberg-sensor sensitivity, dynamic range, and calibrated electric-field response across VHF, UHF, and microwave frequencies.
  • RF-dressed atomic physics: studying AC Stark shifts, Autler-Townes structure, arbitrary RF polarization, Floquet replicas, multiphoton coupling pathways, and avoided crossings in Rydberg-EIT spectra.
  • Nonlinear and heterodyne response: investigating intermodulation, beat-note detection, signal fidelity, and model-to-measurement behavior in Rydberg RF receivers.

Featured Research • arXiv 2026

AoA from Stark-Shifted Rydberg-EIT Spectra

Demonstrates phase-independent angle-of-arrival determination from the relative amplitudes of AC Stark-shifted Rydberg-EIT magnetic-sublevel resonances measured at a single spatial location.

arXiv:2609.17459
Angle-of-Arrival Determination of Radio-Frequency Fields Using Stark-Shifted Rydberg-EIT Spectra.
View preprint →

Featured Research • arXiv 2026

Floquet Interpretation of Avoided Crossings

Interprets avoided crossings in AC Stark-shifted Rydberg-EIT spectra through Floquet/Shirley modeling, connecting measured spectral structure to RF-dressed states, Floquet replicas, and multiphoton coupling pathways.

arXiv:2609.06062
Floquet Interpretation of Avoided Crossings in AC Stark-Shifted Rydberg-EIT Spectra.
View preprint →

Featured Research • Journal of Applied Physics 2025

Subwavelength RF Angle-of-Arrival Sensing

Demonstrates RF angle-of-arrival estimation from amplitude-only standing-wave measurements within a deeply subwavelength Rydberg-atom sensing region, avoiding a conventional phase-resolved antenna-array architecture.

Journal of Applied Physics, 2025
Compact Rydberg-atom direction finding using subwavelength field measurements.
View publication →

Professional Experience

2024–Present • Boulder, Colorado

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.

2021–2023 • Bengaluru, India

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.

2020–2021 • Chennai, India

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.

2010–2012 • Maharashtra, India

Junior Telecom Officer — BSNL

Worked with wired telephony, 2G/3G cellular systems, optical-fiber networks, and customer-facing telecommunications operations.

Selected Engineering Projects

Ansys • System-Level RF

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.

Digital beamforming system simulation

IIT Madras • 5G Hardware

3.5 GHz Bandpass Filter

Designed, fabricated, and experimentally validated a passive 3.5 GHz bandpass filter for the IIT Madras 5G Testbed.

3.5 GHz 5G bandpass filter

IITMSAT • Satellite Communications

Antenna, Polarization & Link Analysis

Analyzed spacecraft attitude, antenna radiation patterns, LHCP/RHCP polarization, orbital visibility, and link budgets for a LEO satellite communication system.

Related publication →

IITMSAT satellite communication simulation

Doctoral Research • Electromagnetics

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.

Spherical harmonic representation of electromagnetic radiation

Selected Publications

Selected work is shown below. Complete records: Google Scholar · Web of Science · ORCID

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.
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.
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.
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.
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.
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

Contributor to patent-related Rydberg sensing inventions

Rydberg Field Imaging

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 RF Angle of Arrival

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

Growing Reference • Electromagnetics & RF

EM Notes — Created using ChatGPT

A growing technical reference created using ChatGPT, covering electromagnetics, antennas, RF and microwave systems, computational methods, sensing, quantum-enabled RF concepts, and engineering applications.

Explore EM Notes →

Education

University of Colorado Boulder

Ph.D., Electrical Engineering — Quantum Sensing

Expected 2026 • GPA 3.83/4.00

M.S., Electrical Engineering

2025 • GPA 3.83/4.00

IIT Madras

Ph.D., Electrical Engineering — RF & Microwave

2021 • CGPA 8.34/10

Ph.D. thesis on Shodhganga →

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