Quantum dot-based indistinguishable and entangled photon sources at telecom wavelengths

Project goal is to investigate experimentally possibility of generation indistinguishable photons and entangled photon pairs from epitaxial quantum dots (QDs) integrated into optimized photonic structures emitting at telecom wavelengths (1.3-1.55) µm. These states are crucial for implementation of advanced quantum computation and communication schemes (e.g., quantum repeater) in the NIR in order to bring them closer to practical limits (compatibility with existing fiber networks or silicon photonics). For the project strain-engineered GaAs- and InP-based QDs will be used. To demonstrate and optimize indistinguishability of consecutive photons two-photon interference will be measured. For polarization entanglement biexciton-exciton cascade with external control of fine structure splitting will be tested by cross-correlation measurements in various polarization bases and quantum tomography of two-photon state. The key experiments will be specially set for IR detection.

Key responsibilities of the PhD student includes:
1. Setting a Hong-Ou-Mandel interferometer
2. Determination of and entanglement fidelity and indistinguishability of photons emitted from QD structures
3. Experimental determination of extraction efficiency from QD-nanophotonic structures