@bachelorsthesis{1998B,
  title={Holographic notch filter multi-channel Raman spectrometer for single crystal measurements},
  author={Adan Brown},
  month={May},
  year={1998},
  abstract={A commercial Raman spectrometer was improved and optimized through the introduction of a holographic
supernotch filter and a band-pass filter to allow for measurements of single crystal samples. It is
shown that the holographic filter improves by several orders of magnitude the discrimination of
stray light. Laser plasma lines are also considerably reduced in intensity by the band-pass
filter. A calibration technique for the Raman spectrometer was developed using these plasma lines.
The calibration was tested by obtaining the vibrational Raman spectra of silicon and germanium.
In each case the first-order phonon was found to be within \B12 wavenumbers of
literature values, which is consistent with the resolution of the CCD camera detector. The
limitations of the present setup were explored and tested. It was found that plasma lines
could still be observed in the spectrum of very weakly scattering samples and that the fidelity
of the instrument could be greatly improved by avoiding some of the functions of the controlling
software provided by the manufacturer. In particular, it was shown that opening and closing a
shutter directly in front of the CCD camera caused undesirable variations in its operating
temperature which resulted in unreliable spectral baseline values. The potential for the Raman
system to aid in materials characterization was demonstrated with measurements of the Raman
scattering spectra of crystals of strontium titanate, and of the Cu-Nb-O system. It was shown that the Cu-Nb-O crystal investigated (the
structure of which is currently still unknown) had a high degree of anisotropy. Its spectrum was
compared to that of ceramic samples of known composition, namely CuNbO<sub>3</sub> and 
CuNb<sub>2</sub>O<sub>3</sub> which could as a result be unambiguously eliminated as
possibilities.},
  note={Supervised by M. Reedyk}
}