Photon localization in resonant media

Phys Rev Lett. 2001 Oct 8;87(15):153901. doi: 10.1103/PhysRevLett.87.153901. Epub 2001 Sep 19.

Abstract

We report measurements of microwave transmission over the first five Mie resonances of alumina spheres randomly positioned in a waveguide. Though precipitous drops in transmission and sharp peaks in the photon transit time are found near all resonances, measurements of transmission fluctuations show that localization occurs only in a narrow frequency window above the first resonance. There the drop in the photon density of states is found to be more pronounced than the fall in the photon transit time above the resonance, leading to a minimum in the Thouless number.