Page perso : http://inac.cea.fr/Phocea/Membres/Annuaire/?uid=jmgerard
Labo : http://inac.cea.fr/en/Phocea/Vie_des_labos/Ast/ast_service.php?id_unit=1150
Quantum sources of light such as single photon sources (SPS) and sources of entangled photon pairs (SEPP) are a key resource for quantum communications, photonic quantum computing and simulation, and quantum sensing. In spite of important advances over the last 15 years, present day sources are still far from real applications to quantum engineering : 1) highly efficient single photon sources have not yet been demonstrated at telecom wavelength (which is essential for quantum communications); 2) spectral- tuning has to be developed to match the emission wavelength of several SPS to a given target wavelength; 3) the efficiency of the best SEPP is presently limited to 0.1 pair per pulse.
This PhD project will target the development of practical sources for photonic quantum engineering, and will solve these three issues by following a highly innovative approach. We will start from the “photonic trumpet” geometry introduced by INAC in 2013, which has already enabled the demonstration of record-efficiency SPS and is (unlike microcavities!) well suited to collect light over a wide spectral range. We will use material strain as a tuning knob to tailor the optical properties of an embedded quantum dot (QD) : we will target bandgap tuning over a wide range, and the cancellation of the fine exciton splitting due to QD asymmetry in view of entangled pair generation. Integration of the trumpets on piezoelectric transducers and bending of the trumpets using electrostatic effects will both be explored as means to apply additional strain to the QD. The PhD will take part to the nanofabrication of the sources, and will take in charge their study (efficiency, purity, tunability, degree of entanglement) using optical spectroscopy and quantum optics techniques.