Effects of disorder on optical and electron spin linewidths in Er3+,Sc3+:Y2SiO5

The material Er3+:Y2SiO5 co-doped with Sc3+ is investigated for applications in optical quantum storage and signal processing. Replacing 1% of the Y3+ in the crystal with Sc3+ introduces static strain into the lattice that increases the inhomogeneous linewidth of the Er3+ optical transition at 1.536 μm to 25 GHz, a 50-fold increase compared to Er3+:Y2SiO5 samples without Sc3+ co-doping. Electron paramagnetic resonance spectroscopy shows that electron spin linewidths are also strongly increased, confirming the previously proposed mechanism for decoherence suppression by using disorder to inhibit resonant spin-spin interactions. Analysis of the spin line broadening as a function of magnetic field orientation indicates the presence of contributions that cannot be modeled by a simple change in the electronic g tensor. Optical homogeneous linewidths of less than 2 kHz are observed for a weak magnetic field of 0.1 T and also for fields greater than 2 T with the field oriented near the D2 crystal axis and at a temperature of 1.7 K. These results suggest that this material can be useful for high-bandwidth classical and quantum information processing in the telecom C-band.