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Title: Finite element characterisation of terahertz waveguides and devices
Author: Tanvir, Huda Muhammed
ISNI:       0000 0004 2716 3176
Awarding Body: City University
Current Institution: City, University of London
Date of Award: 2012
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In recent years, there has been considerable interest in exploiting the frequency bands in the terahertz regime to open up new frontiers of research across a diverse range of applications. An array of opportunities for creating novel technologies using this frequency band had remained largely unexplored and undeveloped for a considerable period of time due to the lack of suitable sources, as well as lack of guiding and detecting devices. With the advent of quantum cascade lasers, a new frontier for generating terahertz radiation through using compact sources has emerged. However, the lack of availability of waveguides that offers low loss and better beam quality with high power still restricts the usage of quantum cascade lasers in many practical THz systems. This thesis describes the design, analysis and optimisation of waveguides used in various terahertz quantum cascade lasers. A fully vectorial H-field based finite element method has been used in the research reported in this thesis to reveal the modal characteristics of various quantum cascade laser waveguides. The simula› tion method was also used to identify an adverse mode coupling phenomenon in a quantum cascade laser waveguide that can potentially degrade the performance of the device. Finally, an enhanced design of a wavegutde is also proposed here where it is shown that a considerable advancement can be achieved in improving the beam quality of a terahertz quantum cascade laser.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available