Multifold wave-particle quantum correlations in strongly correlated three-photon emissions from filtered resonance fluorescence.

Multifold wave-particle quantum correlations are studied in strongly correlated three-photon emissions from the Mollow triplet via frequency engineering. The nonclassicality and the non-Gaussianity of the filtered field are discussed by correlating intensity signal and correlated balanced homodyne signals. Due to the non-Gaussian fluctuations in the Mollow triplet, new forms of the criterion of nonclassicality for non-Gaussian radiation are proposed by introducing intensity-dual quadrature correlation functions, which contain the information about strongly correlated three-photon emissions of the Mollow triplet. In addition, the time-dependent dynamics of non-Gaussian fluctuations of the filtered field is studied, which displays conspicuous asymmetry. Physically, the asymmetrical evolution of non-Gaussian fluctuations can be attributed to the different transition dynamics of the laser-dressed quantum emitter revealed by the past quantum state and conditional quantum state. Compared with the conventional three-photon intensity correlations that unilaterally reflect the particle properties of radiation, the multifold wave-particle correlation functions we proposed may convey more information about wave-particle duality of radiation, such as the quantum coherence of photon triplet and "which-path" in cascaded photon emissions in atomic systems.