Thesis (MSc)--University of Stellenbosch, 2003. / ENGLISH ABSTRACT: The efficient manipulation of various nonlinear optical processes frequently requires the
shaping of the laser beams used for these processes. Three beam shaping techniques were investigated
in this thesis. The focussing of Gaussian laser beams was investigated analytically, in
order to efficiently manipulate the focussed beam characteristics. The beam-shaping characteristics
of a diffractive optical element (DOE) was investigated numerically, which illustrates the beamshaping
capability of the DOE, and identifies the critical parameters in experimental situations.
The use of a waveguide as beam shaping device was investigated analytically and experimentally,
and characterized for use with the available tunable laser sources. A Raman laser, or Raman shifter,
employs stimulated vibrational Raman scattering to generate laser radiation at shifted frequencies.
The waveguide was successfully applied as a beam shaping device in the Raman laser system, for
optimisation of the process. The Raman laser system was investigated experimentally and characterized
for use with the available tunable laser sources. The successful generation of laser radiation
at shifted frequencies illustrates the usefulness of the system for generating tunable red-shifted frequencies.
The results of this work allow the simple and efficient application of the Raman laser to
generate laser radiation at shifted frequencies, in particular tunable infrared laser radiation which
is desirable for molecular spectroscopy. / AFRIKAANSE OPSOMMING: Nie-liniêre optiese prosesse kan meer effektief benut word deur die vervorming van die laserbundels
wat gebruik word in die prosesse. In hierdie tesis word drie laserbundel-vervormings tegnieke
ondersoek. Die fokussering van Gaussiese laserbundels word analities ondersoek, om die
gefokusseerde bundel se eienskappe effektief te manipuleer. Die bundel-vervormings eienskappe
van ’n diffraktiewe optiese element word numeries ondersoek, wat die effektiwiteit van die bundelvervorming
en die sensitiewe parameters in die sisteem uitwys. Die gebruik van ’n golfgeleier as ’n
bundel-vervormings tegniek word ook analities en eksperimenteel ondersoek, en gekarakteriseer
vir gebruik met die gegewe golflengte-verstelbare laser sisteme. ’n Raman laser, wat gestimuleerde
vibrasionele Raman verstrooiing gebruik om laser lig te genereer by Stokes-verskuifde frekwensies,
word ondersoek. Die golfgeleier word effektief gebruik as ’n bundel-vervormings tegniek in
die Raman laser, om die bogenoemde nie-liniêre proses te optimeer. Die Raman laser was eksperimenteel
ondersoek en gekarakteriseer vir gebruik met die gegewe golflengte-verstelbare lasers.
Laser lig by verskuifde golflengtes is suksesvol gegenereer, wat die bruikbaarheid van die sisteem
illustreer. Van belang is spesifiek verstelbare infrarooi laser lig, wat gebruik kan word in die
laser-spektroskopie van molekules. Die resultate van hierdie werk lei tot die eenvoudige en effektiewe
gebruik van die Raman laser, om langer golflengtes in die infrarooi gebied te genereer met
’n gegewe laser in die sigbare gebied.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:sun/oai:scholar.sun.ac.za:10019.1/16313 |
| Date | 04 1900 |
| Creators | Du Plessis, Anton |
| Contributors | Rohwer, E.G., Von Bergmann, H.M., University of Stellenbosch. Faculty of Science. Dept. of Physics. |
| Publisher | Stellenbosch : University of Stellenbosch |
| Source Sets | South African National ETD Portal |
| Language | en_ZA |
| Detected Language | English |
| Type | Thesis |
| Format | 110 leaves : ill. |
| Rights | University of Stellenbosch |
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