Carrier dynamics of single InAs Quantum Dots studied by two colour intensity interferometry correlation

Actual research in single semiconductor quantum dot field has lead to new quantum technology devices, like single photon and entangled photon emitting diodes. [1] Incoming initiatives around this research area push these present advances to a more complex situation: quantum gating devices. Single QD spectroscopy reveals interesting properties for quantum logic gating operations. Exciton and biexciton quantum state population behaves as a two level system following Rabi oscillations. It has been proposed CNOT [2] and CROT [3,4] quantum gates using the biexciton to exciton recombination properties in InAs single QDs (SQDs). All these efforts suggest new near future possibilities to implement all in one optical devices to obtain efficient quantum logic operations, with the capabilities to address new photonic challenges to the advantages of the well know semiconductor technologies. Here we present a detailed study of single photon correlation experiment under two colour laser excitation. We developed an adaptation of the Master Equations for the Microstates (MEM) to reproduce the capture, escape and recombination dynamics of the ground exciton states confined in a single InAs QD.(5) The model reproduces the power evolution of each excitonic complex emission (figure 1.a) and their photon correlation coincidence histograms, both in autocorrelation and cross-correlation schemes (figure 1.b), with single or two colour lasing excitation. This procedure can be also applied to different single QDs with particular charge environment. The unintentionally impurity QD surrounding modify the regeneration and the single carrier escape times. Furthermore, the physical feeding process of each excitonic complex does not follow a linear dependence on either excitation power or excitation wavelength. Its specific dynamics leads to not negligible shape changes in the photon correlation pattern. Under convenient power excitation conditions and using two laser sources we demonstrate that these QDs exhibits a 100 % single photon optical switching, which could be used as the basis for ultra fast single photon logic devices.