A proof of concept virtual reality system is presented that integrates ultrasonic feedback sensations to provide a demonstrative virtual reality exposure therapy environment containing multiple scenarios with virtual spiders. This system and environment were utilised to conduct a study containing 35 participants with the goal of investigating the effect the environment could have on their level of anxiety. This level of anxiety was measured in three different forms: changes in frontal asymmetry analysis of EEG data, changes in skin conductance levels and subjective units of distress. The Fear of Spiders Questionnaire was used to determine which participants in the study reported to be moderately afraid of spiders. For these participants all three measurement forms for anxiety showed statistically significant increases in a comparison between baseline and scenarios with the virtual spiders. A statistically significant correlation between scores on the Fear of Spiders Questionnaire and changes in anxiety shows the system to have had a greater effect on the anxiety levels of those who were more afraid of spiders, than those who were not. There was also a statistically significant correlation discovered between immersion and increase in anxiety, highlighting the significance of immersion in future virtual reality exposure therapy applications.

The following presents a comparison of an extrinsic Fabry–Perot interferometer (EFPI)-based temperature sensor, constructed using a novel diaphragm manufacturing technique, with a reference all-glass EFPI temperature sensor. The novel diaphragm was manufactured using polyvinyl alcohol (PVA). The novel sensor fabrication involved fusing a single-mode fibre (SMF) to a length of fused quartz capillary, which has an inner diameter of 132 μm and a 220 μm outer diameter. The capillary was subsequently polished until the distal face of the capillary extended approximately 60 μm beyond that of the single mode fibre. Upon completion of polishing, the assembly is immersed in a solution of PVA. Controlled extraction resulted in creation of a thin diaphragm while simultaneously applying a protective coating to the fusion point of the SMF and capillary. The EFPI sensor is subsequently sealed in a second fluid-filled capillary, thereby creating a novel temperature sensor structure. Both temperature sensors were placed in a thermogravimetric analyser and heated from an indicated 30 °C to 100 °C to qualitatively compare sensitivities. Initial results indicated that the novel manufacturing technique both expedited production and produces a more sensitive sensor when compared to an all-glass construction.

While ever higher resolution temperature sensing is of demand in research and industry, the cost of sensors in the sub-milli-Kelvin (mK) range can be restrictive. Furthermore, as the majority of commercial temperature sensor measurements are transmitted via electrical circuits, significant post-processing is required to obtain a high-resolution due to phenomena such as electromagnetic interference, self-heating, electrical noise, etc. Consequentially, research in recent years has focused on the development of several technologies which overcome this issue, with optical fibre sensors proving to be a viable option. Owing to this, the following chapter will aim to review the current state-of-the-art in liquid filled optical fibre temperature sensing and the underlying methods.

This paper presents preliminary results on the evaluation of a novel optical fibre based sensor for the measurement of incident ionising radiation. The sensor is designed to be extremely sensitive to variations in temperature and the hypothesis being explored is that incident ionising radiation will generate some degree of heat in the sensor itself and its surrounding environment, which may in turn be measured with high resolution. Experiments were conducted on a radiotherapy linear accelerator for two clinical doses of 100 MU at 6 MV and 10 MV, in addition to this one non-clinical dose of 10,204 MU at 10 MV was performed. Results indicated that the sensor in its current configuration, while temperature sensitive, was unsuitable for measuring clinical levels of radiotherapy incident ionising radiation and further work is required to achieve the desired outcome.

A novel Fabry-Perot sensor, comprised a glass sphere bonded to a capillary and singlemode fiber, is proposed for refractive index sensing. It is characterized in air, water, ethanol, isopropanol, and glycerol.