TY - GEN
T1 - Isotopically Pure Silcon-28 Whispering Gallery Mode Resonators
T2 - 2018 Conference on Optoelectronic and Microelectronic Materials and Devices, COMMAD 2018
AU - Tobar, Michael E.
AU - Bourhill, Jeremy
AU - Goryachev, Maxim
AU - Creedon, Daniel
AU - Johnson, Brett C.
AU - Jamieson, David
PY - 2018/7/2
Y1 - 2018/7/2
N2 - Single crystal isotopically pure 28Si cylindrical Whispering Gallery (WG) mode resonators have been machined from a rod of isotopically pure crystal. Before machining, the rod was loaded into a cavity with the best Bragg confined modes exhibiting Q-factors above a million for frequencies between 10 and 15 GHz. Electron Spin Resonance spectroscopy revealed a very narrow linewidth spin transition, with g-factor of 1.995±0.008. Analysis determined an upper limit to the linewidth of 7 kHz and a concentration of less than 1011 spins/cm3 (10 parts per trillion). After machining into WG mode resonators, the measured frequencies of the fundamental mode families were used to determine the relative permittivity of the material near 4 K and 20 mK to be 11.488±0.024, with the precision limited only by the dimensional accuracy of the resonator. However, the Q-factors were degraded to below 40,000. Raman spectroscopy revealed strain induced broadening on the radial surface of the crystal as a result of the machining. After an acid clean and etch, followed by annealing, the surface damage was repaired. Subsequently, high Q-factors were also restored. The next step will be to purposefully implant ions to try and realise narrow linewidth spin ensembles with clock transitions, which will couple to high-Q WG modes inside the crystal.
AB - Single crystal isotopically pure 28Si cylindrical Whispering Gallery (WG) mode resonators have been machined from a rod of isotopically pure crystal. Before machining, the rod was loaded into a cavity with the best Bragg confined modes exhibiting Q-factors above a million for frequencies between 10 and 15 GHz. Electron Spin Resonance spectroscopy revealed a very narrow linewidth spin transition, with g-factor of 1.995±0.008. Analysis determined an upper limit to the linewidth of 7 kHz and a concentration of less than 1011 spins/cm3 (10 parts per trillion). After machining into WG mode resonators, the measured frequencies of the fundamental mode families were used to determine the relative permittivity of the material near 4 K and 20 mK to be 11.488±0.024, with the precision limited only by the dimensional accuracy of the resonator. However, the Q-factors were degraded to below 40,000. Raman spectroscopy revealed strain induced broadening on the radial surface of the crystal as a result of the machining. After an acid clean and etch, followed by annealing, the surface damage was repaired. Subsequently, high Q-factors were also restored. The next step will be to purposefully implant ions to try and realise narrow linewidth spin ensembles with clock transitions, which will couple to high-Q WG modes inside the crystal.
UR - http://www.scopus.com/inward/record.url?scp=85066742072&partnerID=8YFLogxK
U2 - 10.1109/COMMAD.2018.8715244
DO - 10.1109/COMMAD.2018.8715244
M3 - Conference paper
AN - SCOPUS:85066742072
T3 - 2018 Conference on Optoelectronic and Microelectronic Materials and Devices, COMMAD 2018
SP - 41
EP - 42
BT - 2018 Conference on Optoelectronic and Microelectronic Materials and Devices, COMMAD 2018
PB - IEEE, Institute of Electrical and Electronics Engineers
Y2 - 9 December 2018 through 13 December 2018
ER -