High brightness light sources for defence applications
Abstract
This thesis contains the results of the work that was carried out between February 2009 and September 2012 in the area of high brightness light sources for defence applications. The work follows two main themes, namely nonlinearity in optical fibres and optical parametric oscillators (OPOs). Initially, the prospect of creating an ultrafast light source from solid core microstructured fibre via the phenomenon of modulation instability is discussed alongside supercontinuum generation and its value as a broad bandwidth source in countermeasures. What follows concerns OPOs in the infrared, both external (extracavity) and internal (intracavity) to a laser cavity, with the former is of benefit for high power applications, whereas the latter allows the OPO to operate more effectively at lower powers. The extracavity OPO section discusses a 2-stage conversion from 1064nm to 2128nm with the second stage design for conversion to ~5000nm, and the intracavity work is directed at both enabling a single frequency source for spectroscopy and examining the relationship between output coupling and the resonant OPO and laser fields.