Quantum correlations measured with multi-pixel detectors
Abstract
This thesis investigates the measurement of spatial correlations of photon pairs generated
through spontaneous parametric down-conversion with single-photon sensitive
multi-pixel detectors.
A custom designed and fabricated 8£1 fibre array detector for time to position multiplexing
was characterised. This detector was then commissioned in an experiment
measuring the spatial correlations of photon pairs in position, momentum and intermediate
bases. The fibre array measured eight positions simultaneously with one
Single-Photon Avalanche Diode, which led to an eight-fold increase in the data acquisition
rate compared to traditional experiments, where a single SPAD was scanned
across the detection plane.
To capture all of the emitted light, an electron-multiplying CCD (EMCCD) camera was
used. The spatial correlations were measured for the first time in momentumand position
bases with a single-photon sensitive camera. Additionally, over 2500 spatial states
were accessed,which, to date, is the highest number of accessed states, using the transverse
positions of correlated photon pairs.
The detected photon pairs were tested, if they fulfil the requirements of entanglement.
The calculated variance product was 1 order of magnitude and almost three orders of
magnitude below the classical limit of separability for the fibre array and the EMCCD
camera respectively.
Finally the image enhancement of using a correlated light source with a noise rejection
algorithm was investigated experimentally and theoretically.