Fluorescence Intermittency of A Single Quantum System and Anderson Localization

The nature of fluorescence intermittency for semiconductor quantum dots (QD) and single molecules (SM) is proposed as a manifestation of Anderson localization. The power law like distribution for the \emph{on} time is explained as due to the interaction between QD/SM with a random environment. In particular, we find that the \emph{on}-time probability distribution behaves differently in localized and delocalized regimes. They, when properly scaled, are \emph{universal} for different QD/SM systems. The \emph{on}-time probability distribution function in the delocalized QD/SM regime can be approximated by power laws with exponents covering $-2\le m <0$. QD/SM switches to a dark (\emph{off}) state when a charge of QD/SM hops into the trap states, which becomes localized after stabilization by the surrounding matrix.