ph9b01300_si_001.pdf (1.61 MB)
Coherence and Interaction in Confined Room-Temperature Polariton Condensates with Frenkel Excitons
journal contribution
posted on 2020-01-09, 21:15 authored by Simon Betzold, Marco Dusel, Oleksandr Kyriienko, Christof P. Dietrich, Sebastian Klembt, Jürgen Ohmer, Utz Fischer, Ivan A. Shelykh, Christian Schneider, Sven HöflingStrong
light–matter coupling of a photon mode to tightly
bound Frenkel excitons in organic materials has emerged as a versatile,
room-temperature platform to study nonlinear many-particle physics
and bosonic condensation. However, various aspects of the optical
response of Frenkel excitons in this regime remained largely unexplored.
Here, a hemispheric optical cavity filled with the fluorescent protein
mCherry is utilized to address two important questions. First, combining
the high quality factor of the microcavity with a well-defined mode
structure allows to address whether temporal coherence in such systems
can be competitive with their low-temperature counterparts. To this
end, a coherence time greater than 150 ps is evidenced via interferometry,
which exceeds the polariton lifetime by 2 orders of magnitude. Second,
the narrow line width of the device allows to reliably trace the emission
energy of the condensate with increasing particle density and thus
to establish a fundamental picture that quantitatively explains the
core nonlinear processes. It is found that the blue-shift of the Frenkel
exciton–polaritons is largely dominated by the reduction of
the Rabi splitting due to phase space filling effects, which is influenced
by the redistribution of polaritons in the system. The highly coherent
emission at ambient conditions establishes organic materials as a
promising active medium in room-temperature polariton lasers, and
the detailed insights on the nonlinearity are of great benefit toward
implementing nonlinear polaritonic devices, optical switches, and
lattices based on exciton–polaritons at room temperature.