Université Paris Diderot, Sorbonne Paris Cité, Laboratoire Matériaux et Phénomènes Quantiques, UMR7162, 75013 Paris, France.
Phys Rev Lett. 2012 Dec 14;109(24):246808. doi: 10.1103/PhysRevLett.109.246808.
In this Letter we investigate a low dimensional semiconductor system, in which the light-matter interaction is enhanced by the cooperative behavior of a large number of dipolar oscillators, at different frequencies, mutually phase locked by Coulomb interaction. We experimentally and theoretically demonstrate that, owing to this phenomenon, the optical response of a semiconductor quantum well with several occupied subbands is a single sharp resonance, associated with the excitation of a bright multisubband plasmon. This effect illustrates how the whole oscillator strength of a two-dimensional system can be concentrated into a single resonance independently from the shape of the confining potential. When this cooperative excitation is tuned in resonance with a cavity mode, their coupling strength can be increased monotonically with the electronic density, allowing the achievement of the ultrastrong coupling regime up to room temperature.
在这封信件中，我们研究了一种低维半导体系统，其中大量的、相互间通过库仑相互作用实现相位锁定的、不同频率的偶极子振荡器的协同行为增强了光与物质的相互作用。我们通过实验和理论证明，由于这种现象，具有几个占据子带的半导体量子阱的光学响应是一个单一的尖锐共振，与一个亮的多子带等离子体的激发相关联。这种效应说明了二维系统的整体振子强度如何能够独立于限制势的形状而集中到一个单一的共振中。当这种协同激发与腔模调谐到共振时，它们的耦合强度可以随着电子密度的增加而单调增加，从而允许在室温下达到超强耦合状态。
