Nonclassical higher-order photon correlations with a quantum dot strongly coupled to a photonic-crystal nanocavity

Abstract

We use the third- and fourth-order autocorrelation functions ${g}^{(3)}({\ensuremath{\tau}}_{1},{\ensuremath{\tau}}_{2})$ and ${g}^{(4)}({\ensuremath{\tau}}_{1},{\ensuremath{\tau}}_{2},{\ensuremath{\tau}}_{3})$ to detect the nonclassical character of the light transmitted through a photonic-crystal nanocavity containing a strongly coupled quantum dot probed with a train of coherent light pulses. We contrast the value of ${g}^{(3)}(0,0)$ with the conventionally used ${g}^{(2)}(0)$ and demonstrate that, in addition to being necessary for detecting two-photon states emitted by a low-intensity source, ${g}^{(3)}$ provides a more clear indication of the nonclassical character of a light source. We also present preliminary data that demonstrates bunching in the fourth-order autocorrelation function ${g}^{(4)}({\ensuremath{\tau}}_{1},{\ensuremath{\tau}}_{2},{\ensuremath{\tau}}_{3})$ as the first step toward detecting three-photon states.