Optical decoherence studies of yttrium oxyorthosilicate Y2SiO5 codoped with Er3+ and Eu3+ for optical signal processing and quantum information applications at 1.5 microns

We report detailed studies of the optical decoherence and spectroscopic properties of the 1536-nm optical transition of the bandwidth-engineered material 0.02% Er:1%Eu:Y2SiO5. This work is motivated by the need for comprehensive understanding of new resonant optical materials for spatial-spectral holography and quantum information applications. The dependence of optical decoherence on excitation frequency, applied magnetic field strength and orientation, crystal temperature, measurement time scale, and optical excitation density was studied using stimulated photon echo spectroscopy and time-resolved spectral hole-burning techniques. The effects of weak disorder generated by the introduction of Eu3+ ions into the lattice was probed by comparing measurements across the static disorder-induced distribution of transition frequencies as well as by comparing with measurements on 0.02% Er:Y2SiO5. The results reveal that the coherence properties of Er:Y2SiO5 are preserved in the disordered system; moreover, the increased inhomogeneity produced by the disorder acts to suppress optical decoherence by inhibiting the electronic spin diffusion process, improving material properties for low magnetic field strengths and at increased temperatures desirable for practical applications.