Nonlocal optical response of weakly confined excitons in Cu 2 O mesoscopic films

作者：Mitsuyoshi Takahata, Kōichiro Tanaka, N. Naka · 发表于：Physical review. B./Physical review. B · 年份：2018 · DOI：10.1103/physrevb.97.205305 · 被引用次数：25 · 研究领域：Strong Light-Matter Interactions、Quantum and electron transport phenomena、Physics of Superconductivity and Magnetism

We have demonstrated size-dependent radiative coupling in a ${\mathrm{Cu}}_{2}\mathrm{O}$ mesoscopic film, where the spatial matching between the center-of-mass exciton motion and light waves plays an essential role. The observed quadratic increase and oscillation of the photoluminescence intensity with varying film thicknesses (16--1000 nm) indicate a nonlocal response that is unique to mesoscopic systems. Optimally, a ${10}^{4}$-fold enhanced radiative rate was found compared with bulk ${\mathrm{Cu}}_{2}\mathrm{O}$. A new degree of freedom in the light-matter interaction is presented, which differs from the mode volume control in cavity quantum electrodynamics.