Physical Sciences and Mathematics Commons^™

Real-Time Characterisation Of Dynamic Laser Fields, Thomas Butler

Theses

Many modern technologies rely on laser devices, in areas such as communications, sensing, and imaging. Examination and research into the fundamental operational dynamics of lasers, and characterisation of laser performance, are a crucial tool in ensuring the quality and effectiveness of laser-based applications. The development of characterisation tools is an important part of improving upon existing technologies and advancing the next generation of devices.

In this work, a real-time multiheterodyne detection technique is developed which allows for the study of dynamically varying pulse trains formed by optical frequency combs.

Development Of Nanoelectrodes For Electrochemical Applications, Séan Barry

Theses

The demand for direct, selective and rapid determination of chemical and biological analytes has led to a growing interest in electrochemical sensor devices. Particularly the use of nanomaterials and nanoelectrodes has received increased interest due to their enhanced electrochemical properties. In this thesis these enhanced properties are exploited in order to develop multiple sensing applications.

Firstly a sensitive microband based sensor is described for the detection of trinitrotoluene and for its discrimination from other nitroaromatic compounds. Square wave voltammetry was used to identify characteristic reduction peaks for these compounds and a calibration plot for the quantification of TNT was also …

Ultrashort Pulse Generation In Inas Quantum Dot Semiconductors, Patrick Finch

Theses

In this thesis, the effect of operating two-section InAs quantum dot passively mode- locked semiconductor lasers in the random population regime is examined in detail in an attempt to achieve wide optical bandwidths and ultrashort optical pulses. It is demonstrated in this work that large increases in optical bandwidths can be observed in the random population regime. Random population was achieved with an undoped device by lowering the operating temperature to 20 K. An emission bandwidth of 27 nm was measured using an undoped device at 20 K, with corresponding pulses of 290 fs, shorter than any previously reported with …

Low-Cost Fabrication Of Nanoelectrodes For Electrochemical Applications, Colm Barrett

Theses

Compared to traditional macroelectrodes, nanoscale electrodes have tremendous potential when employed in electrochemistry due to enhanced sensitivity arising from increased mass transport to the electrode and low background charging currents. Electrochemically- based diagnostic products such as sensors require sensing elements with greatly enhanced performance and nanoelectrodes offer a viable route to attaining this performance improvement.

Firstly, the fabrication of a polymer microneedle array-based sensor is described and employed to demonstrate a mediated approach for the detection of glucose in solution. This was to demonstrate the feasibility of the system for in-vivo sensing. Cyclic voltammetry was used to achieve detection of …

Emission Properties And Carrier Dynamics Of Iii-V Nanostructures For Next Generation Photonic Devices, Katarzyna Komolibus

Theses

A majority of modern day applications, ranging from telecommunications, charge storage memories and solar cells to more recently silicon photonics, have at their core compound semiconductor based optoelectronic devices. Particular attention has focused on the use of Group-III and Group-V elements in these devices and thus drives a desire for improved understanding. This thesis therefore studies a variety of novel III-V nanostructures, which have shown immense promise for inclusion in next-generation photonic devices, examining in detail these structures in terms of their optical properties and inherent carrier dynamics.