Thesis (MSc)--Stellenbosch University, 2014. / ENGLISH ABSTRACT: Terahertz (THz) radiation is often used in many promising applications such as information
and communication technology and airport security. Optimized and adapted terahertz fields
hold huge promise for leading this technology further. This study is focused on terahertz time
domain spectroscopy (THz-TDS). In THz-TDS the electric field is measured, therefore both
amplitude and phase information of the THz pulse can be obtained. We used the pump-probe
technique in order to measure a THz pulse from the photoconductive antenna. A pulsed fiber
laser with FWHM of ' 100 fs was used for this. The frequency spectrum of the measured THz
pulse was obtained via a fast Fourier transform. We studied the principles of the THz pulse
generation as well as detection, with a photoconductive antenna as emitter and detector. In this
study terahertz spectroscopy has been used to investigate the refractive index and absorption
coefficient of different types of materials in the terahertz region. The last part of this study deals
with a simple process for material parameter extraction of a polymer sample using commercial
software called Teramat1.0. It uses the sample thickness, the reference THz pulse and the
transmitted THz pulse to retrieve the complex refractive index of the sample. / AFRIKAANSE OPSOMMING: Terahertz (THz) straling word gereeld gebruik vir belowende toepassings soos inligting en kommunikasie
tegnologie en lughawe sekuriteit. Geoptimeerde en aangepaste terahertz velde dra by
tot die bevordering van die tegnologie. Hierdie studie fokus op terahertz tyd domein spektroskopie
(THz-TDS). In THz-TDS word die elektriese veld gemeet en dus word beide amplitude
en fase inligting van die THz puls verkry. Ons gebruik ’n pomp en toets tegniek om die THz
puls deur ’n fotogeleidende antenna te bepaal. ’n Gepulseerde vesel laser met FWHM van 100
fs word hiervoor benut. Die frekwensie spektrum van die gemete THz puls word bereken deur
’n vinnige Fourier transvorm te bereken. Die beginsels van die generering en deteksie van THz
pulse is bestudeer met ’n fotogeleidende antenna as sender en ontvanger. In die studie is terahertz
spektroskopie gebruik om die brekingsindekse en die absorpsie koeffisiënte van verskillende
materiale in die terahertz gebied te bepaal. Die laaste gedeelte van die studie handel oor ’n
eenvoudige proses om die materiaal parameters van ’n polimeer te bepaal deur gebruik te maak
van kommersiële sagteware Teramat 1.0. Die monster dikte, die THz verwysingspuls en die
deurgelate puls word gebruik om die komplekse brekingsindeks van die materiaal te bereken.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:sun/oai:scholar.sun.ac.za:10019.1/96030 |
| Date | 12 1900 |
| Creators | Hissen, Huzifa Zain Alabdeen Abdarahman |
| Contributors | Rohwer, Erich G., Neethling, Pieter H., Stellenbosch University. Faculty of Science. Dept. of Physics. |
| Publisher | Stellenbosch : Stellenbosch University |
| Source Sets | South African National ETD Portal |
| Language | en_ZA |
| Detected Language | English |
| Type | Thesis |
| Format | xiv, 99 p. |
| Rights | Stellenbosch University |
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