The strength of the geomagnetic field is a subject of both scientific and public interest, with the decay over the past 160 years leading to speculation as to whether we are entering a geomagnetic reversal. Prior to 1840, there was no capability for direct measurements of geomag…
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A few percent of nitrogen (N) or bimuth (Bi) incorporation in GaAs compound semiconductors have proved to lower significantly its bandgap. This unusual bandgap reduction is of interest for numerous applications such as long wave-length lasers, solar cells etc. However, the addit…
This thesis presents results of lattice QCD computations of the K → π semi-leptonic (Kl3) and pion electromagnetic form factors using partially twisted boundary conditions. These form factors parameterize low-energynon-perturbative strong interaction effects and cannot therefore…
The term `laser cooling' is applied to the use of optical means to cool the motional energies of either atoms and molecules, or micromirrors. In the literature, these two strands are kept largely separate; both, however suffer from severe limitations. Laser cooling of atoms and …
X-ray spectral variability is a powerful probe of the relationship between the accretion disc and corona in accreting compact objects. In this thesis, I present the use of variability techniques to disentangle the different variable components of X-ray spectra. By examining corr…
The Silicon Photomultiplier (SIPM) is a novel photon sensing device, with potential applications in particle physics, astronomy and general gamma-ray spectroscopy. Various SiPM designs were evaluated for these roles by coupling them to a range of scintillators, including LSO, Na…
Cold atom samples, at temperatures of the order 100 uK, are useful for a wide reaching array of new and exciting technological and scientific endeavours. Atoms are conventionally cooled by Doppler cooling, which relies on the continuous absorption and reemission of photons in a …
The first experimental confirmation that femtosecond plasmon pulses can be generated, transmitted and modulated along a metal/dielectric waveguide is achieved. The ultrafast optical modulation of plasmons is accomplished by optical excitation of the aluminium plasmonic waveguide…
Passive acoustics provides a powerful tool for marine mammal research and mitigation of the risk posed by high energy anthropogenic acoustic activities through monitoring animal positions. Animal vocalisations can be detected and utilised in poor visibility conditions and while …
In this thesis, I investigate cladding-pumped Raman fibre lasers and amplifiers. Such devices, offering a novel way to generate Raman gain, combine the advantages of the hugely successful cladding-pumped rare-earth doped fibre lasers with those of stimulated Raman scattering. Th…
The aim of the work presented in this thesis is to investigate adaptively shaped advanced ultrafast laser sources in the near-(NIR) and the mid-infrared (MIR) regimes. The setup involves shaping a NIR pulse using an adaptively controlled liquid crystal spatial light modulator (L…
This thesis presents a series of experimental studies based on using liquid crystals (LC) with planar optical lightwave components. Adaptive optical devices have been fabricated by combining LCs with direct UV written buried channel waveguide and Bragg grating structures. It has…
The main aim of this project was to characterise electrical and optical effects in hybrid liquid crystals. Hybrid form of liquid crystals was achieved by using photoconducting alignment layers in liquid crystals cells and also by including ferroelectric, inorganic nanoparticles …
A well-motivated framework to naturally introduce neutrino masses is the B − L model, a U(1) extension of the standard odel related to the baryon minus lepton gauged number. Besides three right-handed neutrinos, that are included to cancel the anomalies (thereby naturally provid…
Temperature distributions within cores of galaxy clusters indicate gas in the core should cool down rapidly and contract. The cooling flow problem involves the hypothesis that the rapidly cooling gas should eventually condensate into unobserved molecular clouds. Active galactic …
This thesis presents analyses of flickering aurora observed using the state-of-theart Auroral Structure and Kinetics (ASK) multi-monochromatic ground-based auroral imager. Flickering aurora is observed as rapid (typically 2–20 Hz) oscillations in auroral luminosity. There are se…
Recoil Distance Doppler Shift measurements of 182Hg have been performed at the University of Jyväskylä utilising the Köln plunger device. Lifetimes of excited yrast states up to the 10+ state have been measured. The 2+ , 4+ , 6+ , 8+ and 10+ states were found to have lifetimes o…
The main focus of the thesis is the study of low-degree low-frequency solar p modes from the analysis of high-resolution power spectra generated from 20 years of high-quality data collected by the Birmingham Solar Oscillations Network (BiSON) Resonant Scattering Spectrometers (R…