We report a spectroscopic study of the 7F0-5D1 transition of europium
ions in crystal yttrium orthosilicate (Eu3+:Y2SiO5) with a focus on lo
w-temperature properties relevant to its use in time-domain optical da
ta storage. The optical dephasing time T2 for this green transition wa
s found to be approximately 50 mus for Eu3+ in one optical site (site
1) and 56 mus for Eu3+ in the other site (site 2), both of which excee
ded their respective excited-state lifetimes (32 mus for site 1 and 42
mus for site 2). Of the two optical sites, the transition on site 2 h
as a slightly larger inhomogeneous linewidth (approximately 2.7 GHz) b
ut a significantly larger oscillator strength (approximately 6 x 10(-8
)), making it a good candidate for time-domain optical storage. The hy
perfine structures of the transition for both sites were also measured
by spectral hole burning.