A study of satellite lines in Eu3+:Y2SiO5

Abstract

The aim of this project was to perform the basic spectroscopy of europium pair sites in Y2SiO5 crystal doped with Eu3+ ions (Eu3+:Y2SiO5), evaluating their potential to demonstrate a two-qubit gate operation. The optical transitions of these pair sites are called satellite lines, but little is known about their properties. A key goal of the project was to test techniques to associate observed satellite lines in Eu3+:Y2SiO5 with their respective pair site. Excitation spectra of the 7F0 → 5D0 transition were recorded at orthogonal polarisations. The polarisation dependence of satellite lines was compared to that of the two main lines in an attempt to identify the crystallographic sites of the satellite lines. There was no similarity in the properties of the main and satellite lines, suggesting the pair site ions are strongly perturbed from the isolated ions. I measured the optical coherence times and oscillator strengths of four satellite lines and compared the measurements to the main lines to investigate whether this could be used to associate satellite lines to pair sites. The coherence times of the four satellite lines were 122±9 μs, 206±6 μs, 236±9 μs and 299±11 μs. These values were consistent with the main lines, but due to the presence of instantaneous spectral diffusion a comparison could not be made. However, the oscillator strengths of the main lines could be measured, and each satellite line had an oscillator strength similar to one of the main lines, suggesting that this technique could potentially be used to associate satellite lines to pair sites. Of interest for quantum computing is the possibility that two of the satellite lines are caused by degenerate pair coupling, indicating a strong interaction that could be used for two-qubit gates. Show more