Photons are natural carriers of quantum information due to their ease of distribution and long lifetime. This thesis concerns various related aspects of quantum information processing with single photons. Firstly, we demonstrate N -photon entanglement generation through a generalised N×N symmetric beam splitter known as the Bell multiport. A wide variety of 4-photon entangled states as well as ...

We introduce an alternative method for the retrieval of polarisation in the ultraviolet by the satellite spectrometer SCIAMACHY. Unlike the operational polarisation retrieval algorithm, this method does not use the Polarisation Measurement Devices (PMDs) onboard SCIAMACHY, but only requires the reflectance signal. This makes the algorithm more robust and less sensitive to calibration errors cau...

Many animals have sensitivity to the e-vector of linearly polarised light, which may assist in visually mediated behaviours such as navigation, signalling and foraging. However, it is still controversial as to whether birds possess polarisation sensitivity. Several studies have found that altering the polarisation patterns of the broad visual field surrounding birds alters their intended migrat...

Polarisation has proven to be an effective method in the analysis of light reflection in computer vision. It plays an important role in separating reflectance components using cross polarisation settings. Some polarisation based methods have also been presented in the literature for surface orientation estimation, where the incident light is unpolarised. This thesis aims at exploiting the polar...

Today's most widely used method of encoding quantum information in optical qubits is the dual-rail basis, often carried out through polarisation a single photon. On other hand, many stationary carriers – such as atoms couple to light via single-rail which qubit encoded number photons. As such, interconversion between two encodings paramount order achieve cohesive networks. In this pape...

Polarised quark distributions are extracted from semi-inclusive deep inelastic scattering data, which include the additional detection of a leading hadron to providestatisticaìàvour-tagging'. Results are combined from both proton and`neutron' targets to isolate the contributions to the nucleon spin of the individual quark avours, including the sea quarks. Spin asymmetries in the semi-inclusive ...

Nonlinear Compton scattering is calculated for the collision of an electron with a plane wave pulse. A mid infra-red (IR) peak arises in photon spectrum due to long-range interference associated pulse envelope. The case flat-top studied as toy model envelope effects and reduced two final-state momentum integrations; sine-squared numerically. perturbative expansion charge-field coupling reveals ...

The small degree of circular polarisation observed in some synchrotron sources has a frequency dependence that is not consistent with simple predictions based on the intrinsic circular polarisation of synchrotron emission. The suggestion is explored that the circular polarisation arises as a propagation effect within the source. The physical basis of this alternative mechanism is the fact that ...

We discuss the constraints that recent observations place on circular polarisation in AGN. In many sources the circular polarisation is variable on short timescales, indicating that it originates in compact regions of the sources. The best prospects for gleaning further information about circular polarisation are high resolution VLBI and scintillation ‘imaging’ which probe source structure on m...