title: Observation of superradiance by nonlocal wave coupling of light and excitons in CuCl thin films.
abstract: We report the observation of a remarkably strong coupling between light and a multinode-type exciton. The observed radiative decay time reaches the order of 100 fs, which is much faster than the dephasing process of nonradiative scattering. In this high-speed superradiance, the light wave and the excitonic wave in a high-quality thin film form a harmonized wave-wave coupling over a range of multiple wavelengths. This mechanism contradicts the conventional physical description of light-matter interaction based on the long-wavelength approximation.
authors.affiliation: CREST-JST, 4-1-8 Honmachi, Kawaguchi 332-0012, Japan. ichimiya@laser.mp.es.osaka-u.ac.jp
authors.forename: Masayoshi
authors.initials: M
authors.lastname: Ichimiya
authors.forename: Masaaki
authors.initials: M
authors.lastname: Ashida
authors.forename: Hideki
authors.initials: H
authors.lastname: Yasuda
authors.forename: Hajime
authors.initials: H
authors.lastname: Ishihara
authors.forename: Tadashi
authors.initials: T
authors.lastname: Itoh