Seminar: "Cavity QED in the Ultrastrong Coupling Regime" by Prof. Junichiro Kono

Seminar Abstract:

Strong resonant light-matter coupling in a cavity setting is an essential ingredient in fundamental cavity quantum electrodynamics (QED) studies as well as in cavity-QED-based quantum information processing. In particular, a variety of solid-state cavity QED systems have recently been examined, not only for the purpose of developing scalable quantum technologies, but also for exploring novel ground states of condensed matter induced by strong coupling with photons. This talk will first describe our recent observation of collective ultrastrong light-matter coupling in a two-dimensional electron gas in a high-quality-factor terahertz cavity in a quantizing magnetic field, demonstrating a record-high cooperativity [1]. The electron cyclotron resonance peak exhibited splitting into the lower and upper polariton branches with a magnitude that is proportional to the square-root of the electron density, a hallmark of collective vacuum Rabi splitting. Additionally, we have obtained clear and definitive evidence for the vacuum Bloch-Siegert shift due to the breakdown of the rotating-wave approximation. The second part of this talk will present one-dimensional microcavity exciton polaritons in a thin film of aligned carbon nanotubes [2] embedded in a Fabry-Perot cavity, also exhibiting collective ultrastrong light-matter coupling with unusual continuous controllability over the coupling strength through polarization rotation. These experiments open up a variety of new possibilities to combine the traditional disciplines of many-body condensed matter physics and cavity-based quantum optics.

References

1. Q. Zhang et al., Nature Physics 12, 1005 (2016).
2. X. He et al., Nature Nanotechnology 11, 633 (2016).

Biography:

Junichiro Kono received his B.S. and M.S. degrees in applied physics from the University of Tokyo in 1990 and 1992, respectively, and completed his Ph.D. in physics from the State University of New York at Buffalo in 1995.  He was a postdoctoral research associate at the University of California, Santa Barbara, in 1995-1997 and the W. W. Hansen Experimental Physics Laboratory Fellow at Stanford University in 1997-2000.  He joined the Department of Electrical and Computer Engineering of Rice University in 2000 as an Assistant Professor and was promoted to Associate Professor in 2005 and to Professor in 2009.  He is currently a Professor in the Departments of Electrical & Computer Engineering, Physics & Astronomy, and Materials Science & NanoEngineering at Rice University.  Professor Kono was a recipient of the National Science Foundation CAREER Award in 2002 and has been a Fellow of the American Physical Society (APS) since 2009 and a Fellow of the Optical Society (OSA) since 2015.