Creation and Detection of Single Photons

Sammanfattning: A growing number of technologies employ quantum properties in order to produce solutions that surpass the performance of conventional devices, or to execute operations that are fundamentally impossible with classical systems alone. In the field of optical quantum information science, photons are utilized to encode, communicate and manipulate information, making them vitally important. While photon production always constitutes the first step in any optical experiment, in the field of quantum information science, the recording of data through the process of photon detection is an equally crucial final step.This thesis deals with both the single photons generation (based on diamond color defects) and their detection, utilizing a novel type of superconducting detectors. In particular, part one of this thesis is devoted to the construction of custom designed microscope setup, and the development of laboratory experiments, to enable the generation of single photons as well as the investigation of the optical and spin properties of diamond color centers. Confocal microscopy is used for this purpose, as it allows for the identification and addressing of individual color centers that emit only single photons. This microscope also feature an integrated self-built microwave and magnetic hardware setup, which allows for a wide range of spin environment spectroscopy studies. Single photon emission is demonstrated through both photon anti-bunching and Rabi oscillations at room temperature.The second part of the thesis offers an exploration of superconducting single photon detectors through experiment. Since electronics are an essential part of these detectors, the possibility of using a novel alternative scheme based on capacitive readout combined with fast gating to enable simplified readout is demonstrated. This scheme overcomes the limitations of conventional readout schemes, which require large bandwidth amplification and complex counting electronics. Besides photon detection, the capabilities of these detectors are also expanded to include high-energy particles in the MeV energy range, and the detectors are demonstrated to not only detect single α- and β-particles, but to do so with near unity efficiency. Finally, a multipurpose testing station for superconducting detectors is demonstrated with a central objective of optimizing the coupling efficiency of light to the active area of the detector, as well as to allow for a fast exchange of the optical fiber, thereby facilitating an efficient characterization of the detector. The optimization of this coupling efficiency was demonstrated through proof-of-principle experiments.