Abstract:
Bose-Einstein condensation is a remarkable manifestation of quantum
statistics and macroscopic quantum coherence. Superconductivity and
superfluidity have their origin in Bose-Einstein condensation. Ultracold
quantum gases have provided condensates close to the original ideas of
Bose and Einstein, while condensation of polaritons and magnons have
introduced novel concepts of non-equilibrium condensation. We
experimentally demonstrate a Bose-Einstein condensate (BEC) of surface
plasmon polaritons in lattice modes of a metal nanoparticle array [1].
Interaction of the nanoscale-confined surface plasmons with a
room-temperature bath of dye molecules enables thermalization and
condensation in picoseconds. The ultrafast thermalization and
condensation dynamics are revealed by an experiment that exploits
thermalization under propagation and the open cavity character of the
system. A crossover from BEC to usual lasing is realized by tailoring
the band structure. This new condensate of surface plasmon lattice
excitations has promise for future technologies due to its ultrafast,
room-temperature and on-chip nature.
[1] T.K. Hakala, A.J. Moilanen, A.I. Väkeväinen, R. Guo, J.-P.
Martikainen, K.S. Daskalakis, H.T. Rekola, A. Julku, and P. Törmä,
arxiv:1706.01528