Single Ion Detection of Cerium in Y2SiO5 Microcrystals

Sammanfattning: Quantum computing with single instances of rare earth-ions doped into inorganic crystals shows great promise as a scalable design in the field of quantum information. A detectable and controllable single readout ion is necessary for the scheme proposed in Lund to work. Due to its short excited state lifetime and its cyclable 4f-5d transition, cerium has been deemed suitable for just this purpose. The approach taken in Lund for this single cerium detection is to use a homemade confocal microscopy setup. In previous work using this setup on bulk crystals, it has been assumed that the undetectability of single cerium is due to out of focus ions contributing to a noise floor that is higher than the fluorescence signal from a single one. Hence single ion detection is being attempted in microcrystals. This thesis outlines the process behind converting the confocal microscope into a microcrystal detection setup. Subsequently, Ce3+:Y2SiO5 microcrystal spectroscopy experiments were performed. The energy level structure of cerium is reported to be identical to bulk, with a slight shift in wavelength, and the inhomogenous linewidth has proven to be inconclusive, although it hints towards being much wider than in bulk. Quantifying the homogenous linewidth of the cerium ions using Zeeman hole burning techniques was impervious to our attempts.