Synthesis and Assessment of Laser Related Parameters in Colour Centre Containing Diamond. This thesis reports research on the fabrication and assessment of colour centre containing diamond. The advent of affordable single crystal synthetic diamond with low background absorption has motivated renewed interest in whether efficient colour centre lasers can be realised based on diamond. Two types of colour centres were investigated, composed of one or two nitrogen (N) atoms and a vacancy (V): NV and N2V0. Laser action was first reported in 1985 by Rand and DeShazer in a N2V0 containing diamond.The NV centre is one of the most studied defects in diamond, due to the amount of applications harnessing the specific quantum properties of its negatively charged state.A variety of synthesis techniques were used to produce these centres in nitrogen containing diamond. Specifically, irradiation with electrons with the energy of several MeV in combination with high-temperature and high pressure annealing. Techniques to characterise samples include infrared and ultraviolet-visible absorption and photo luminescence spectroscopy.Up to 0.65 ppm1 of NV0 and 0.85 ppm of NV− were generated in synthetic diamond.Up to 2.2 ppm of N for diamond) 2V0 was generated in natural diamond and up to 0.5 ppm in synthetic diamond. These were consistent with the estimations for concentrations thought to be required for efficient pump absorption in a laser context, 0.6 and 0.9 ppm of NV− and N2V0. Luminescence lifetimes of 8±1 and 20±1 ns and peak emission cross-sections of(3.6 ± 0.1) · 10−17 and (1.7 ± 0.1) · 10−17 cm2 were measured for NV−and NV0, respectively; as well as 12±1 ns and (1.5±0.1) · 10−17 cm2 for N2V0.The gain spectrum was estimated using the emission cross section and absorption spectrum. The potential for positive net gain in a NV− containing sample, for realistic inversion levels of β = 0.3, was inferred from these calculations. Although laser operation may be possible with such samples,this has yet to be achieved, indicating that further study of the fabrication and spectroscopy is required. The best N2V0 sample showed less promise,requiring inversion levels of β > 0.5 to achieve positive net gain.
|Date of Award||21 Apr 2020|
- University Of Strathclyde
|Supervisor||Alan Kemp (Supervisor) & Thorsten Ackemann (Supervisor)|