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arXiv · 0910.5445

Formation dynamics of an entangled photon pair -- a temperature dependent analysis

A. Carmele·F. Milde·M. -R. Dachner·M. Bagheri Harouni·R. Rokniknizadeh·M. Richter·A. Knorr
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Abstract

We theoretically study the polarization entanglement of photons generated by the biexciton cascade in a GaAs/InAs semiconductor quantum dot (QD), located in a nano cavity. A detailed analysis of the complex interplay between photon- and carrier coherences and phonons which occurs during the cascade allows us to clearly identify where the entanglement is generated and destroyed. A quantum state tomography is performed for varying exciton fine structure splittings. By constructing an effective multi-phonon Hamiltonian which couples the continuum of the wetting layer states to the QD we investigate the relaxation of the biexciton and exciton states. This consistently introduces a temperature dependence to the cascade. Considering typical Stranski-Karastanov grown QDs, for temperatures around 80 K the degree of entanglement starts to be affected by the dephasing of the exciton states and is ultimately lost above 120 K.

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A. Carmele, F. Milde, M. -R. Dachner, M. Bagheri Harouni, R. Rokniknizadeh, M. Richter, A. Knorr. 2009-10-28. Formation dynamics of an entangled photon pair -- a temperature dependent analysis. https://doi.org/10.1103/physrevb.81.195319

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