Offir Cohen

Research Scientist


Offir Cohen

Primary Research Area

  • AMO / Quantum Physics
390X Loomis Laboratory


Dr. Offir Cohen is a Research Scientist with the Department of Physics and the Frederick Seitz Materials Research Laboratory at the University of Illinois at Urbana-Champaign since 2017. He received his Ph.D. in Atomic and Laser Physics from the University of Oxford; his thesis topic was on engineering photonic-quantum-state sources for quantum information applications. Dr. Cohen has a joint position as an independent researcher leading research in quantum optics theory and experiment and as a staff scientist of the Materials Research Laboratory, providing scientific support in the Laser and Spectroscopy Facility.

Research Interests

  • Atomic, molecular and optical physics, quantum information, nonlinear spectroscopy, and modeling of light-matter interaction

Research Statement

Dr. Cohen's research interest is in both the fundamental and technological aspects of quantum mechanics, including investigating light-matter interactions at the quantum level, creating and analyzing new quantum states, and developing novel approaches with technological implications. He has particular expertise in the quantum state engineering capabilities of optical fibers. This includes experimental and theoretical studies of the dispersion and nonlinear optical properties (spontaneous four-wave mixing) of photonic crystal fibers and polarization-maintaining fibers. His research has resulted in key demonstrations of the utility of optical fibers for quantum information applications such as quantum communication and computation.

Dr. Cohen's current research interests aim at studying, theoretically and experimentally, quantum phenomena involving light and their application to future technologies. Specifically, he is interested in the linear and nonlinear interaction of photons with matter, for the purpose of

  1. Investigating how the statistics and photon-number correlations relate to the nature of the scattering process
  2. Creating new quantum states of light and matter
  3. Developing and implementing new spectroscopic techniques to study quantum dynamics in materials.

The media in which the interactions take place range from bulk material, atomic vapor or molecular vapor, where no geometrical constraints exist; through waveguides and optical fibers, where mode confinement could play a crucial role; to cavities where modal enhancement, suppression and manipulation impact the interaction process. This research has the potential to shed new light on our understanding of light-matter interaction in a range of environments, as well as provide new methods that are potentially useful for quantum and other technologies.

Selected Articles in Journals