טכניון מכון טכנולוגי לישראל
הטכניון מכון טכנולוגי לישראל - בית הספר ללימודי מוסמכים  
Ph.D Thesis
Ph.D StudentWinik Roni
SubjectQuantum Light Sources Probed by Superconducting Single
Photon Detectors
DepartmentDepartment of Nanoscience and Nanotechnology
Supervisors Professor Eyal Buks
Professor David Gershoni
Full Thesis textFull thesis text - English Version


Abstract

The combination of quantum light sources of single and entangled photons with fast and

efficient single photon detectors is an essential requirement for further advances in quantum optics and optical based quantum information processing. Semiconductor quantum dots were demonstrated to be an excellent source of single and entangled photons using the biexciton-exciton radiative cascade. Superconducting single photon detectors outperform other single photon detectors in terms of quantum efficiency, dark counts, and temporal resolution. We use superconducting single photon detectors for performing polarization tomography of entangled photon pairs with unprecedented temporal resolution. Our tomography demonstrates that the pair of photons which is emitted from the radiative cascade of the on-demand photogenerated quantum dot confined biexciton is maximally entangled during the whole radiative decay. In addition, we discuss some options in which the quantum efficiency and temporal resolution of the superconductor detectors can be enhanced. We fabricate plasmonic nanostructures in the vicinity of the detectors and demonstrate enhancement of close to a factor of x5.5 for optimized plasmonic nanoantenna. In a separate work we fabricate an electrically tunable Josephson junction to control the critical current, phase, and amplitude of a current carrying superconducting wire. Our method may be useful for enhancing the quantum efficiency of superconducting detectors, increasing the sensitivity of superconducting quantum interference devices (SQUID) magnetometers, and controlling superconducting qubits.