Several properties of Eu 3+ :Y 2 SiO 5 spectral holes are measured, to assess the suitability of broad-band hole-patterns for use as laser-frequency references. We measure frequency shifts due to magnetic fields, side-features of neighboring spectral holes and changing optical probe power. A precise calibration of a temperature insensitive point is also performed, where the temperature-induced frequency shift is canceled to first order by the pressure-induced shift from the crystal's helium-gas environment.
A stimulated photon-echo study has verified the instantaneous shift (\ensuremath{\le}1 MHz) and subsequent restoration (\ensuremath{\sim}2 ms) of the transition frequency of an impurity ion in a solid when its neighboring ions are exposed to pulsed optical excitation. Experiments were conducted by monitoring the echo intensity for the
7${\mathit{F}}_{0\mathrm{\ensuremath{-}}}^{5}$
D0 transition of Eu ions in one site of
Y2SiO5, while exciting the other site. A photon-echo theory taking account of the stochastic frequency recovery is developed to explain the observations.
Experimental single qubit gate fidelities in the rare-earth quantum computing (REQC) scheme was found to be lower than predicted by simulation of the optical Bloch equations for the system. The cause was believed to be excitation-induced frequency shifts (EFS), so this BSc thesis investigates a model for EFS in Eu:YSO where stochastic frequency shifts are imposed on the ions. This was implemented as a convolution of the solution to the Bloch equations in each time step with a convolution kernel, where the width of the kernel was dependent on the change in excitation. The simulation was run for a 7 µs complex hyperbolic secant pulse, one of the pulses used in previous experiments. The result was decreased fidelity, but not enough to explain the experimental result. This indicates that EFS may not be the main cause of the experimental fidelity losses, but more thorough investigation is required to draw more certain conclusions.