*ITAMP Lunch Seminar*
*Speaker: *Nicholas Rivera (MIT)
*Date:* Thursday, April 5th
*Time:* 12:00-1:00 pm
Includes Pizza.
*Title: Quantum electrodynamics at the surface of a polaritonic medium*
*Abstract: Quantum electrodynamics is one of the most successful theories
in the history of science, d*escribing accurately nearly all known
phenomena involving electromagnetic fields. Central in QED is the concept
of the photon, a quantum of electromagnetic energy with properties such as
energy, momentum, and angular momentum. For photons in complex arrangements
of optical media, these properties are in general very different than in
free space, leading to vastly altered interactions between matter and
electromagnetic fields. As a result, "QED in a medium" features a vast set
of phenomena that either do not exist or are very hard to realize in "free
space QED". For example, QED effects in photonic crystals and optical
cavities have been leveraged to achieve ultrafast spontaneous emission of
light by molecules, vacuum Rabi oscillations, atom-photon bound states in
photonic crystals, and exciton-polariton condensation.
*This talk presents new developments in this field which result
from extreme (nanoscale) confinement of light by optical media supporting
surface polaritons. These polaritons, which include the family of plasmon-,
phonon-, exciton-, or magnon- polaritons, enable new quantum regimes of
interactions with different kinds of matter such as atom-like emitters,
electrons in quantum wells and in electron microscopes, and
ultrarelativistic Dirac fermions. From this theory, we find that nanoscale
confinement of electromagnetic energy enables high-order angular momentum
transfer with light [1], indirect optical transitions
[2], efficient high-order QED processes such as multi-photon spontaneous
emission [3], as well as conversion of plasmons into x-rays and gamma rays
by relativistic electrons, and high-harmonic emission of plasmons by
electrons modulated by mid-to-far-IR driving fields.*
*[1] N. Rivera*, I. Kaminer*, B. Zhen, J.D. Joannopoulos, and M.
Soljacic. Science 353.6296 (2016): 263-269.*
*[2] Y. Kurman, N. Rivera, T. Christensen, S. Tsesses, J.D. Joannopoulos,
M. Soljacic, M. Orenstein, and I. Kaminer. In press.*
*[3] N. Rivera, G. Rosolen, J.D. Joannopoulos, I. Kaminer, and M.
Soljacic. PNAS (2017): 201713538.*
*Location: *B-106 @ Center for Astrophysics (60 Garden Street)
*Directions: *After entering the lobby of the CfA, turn right to enter the
hallway of the B building. In the hallway, turn right again, B-106 will be
at the end of the hallway on the left side.
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