Optical properties of Yb-doped Y2SiO5 thin films

Yb-doped Y2SiO5 thin films Raman active phonons and crystal-field (CF) excitations have been studied by Raman spectroscopy and infrared transmission, and compared to the single crystals results. The thin films, grown on Y2SiO5 undoped substrate, have been co-doped with Ge, Gd or La in order to adjust the lattice mismatch. Raman active phonon bandwidths indicate that thin films present less strains and defects than single crystals. Interesting thin films properties, such as Yb3+ site occupancies and Yb3+–Yb3+ pair interaction types, may be adjusted by the co-dopants. Infrared absorption shows notably that La3+ is a good co-doping ion to enhance selectively one of the two Yb sites and pair satellite contributions. Ge and Gd co-dopants may also be used to form independently Yb3+–Yb3+ ion pairs with either ferromagnetic or antiferromagnetic dominant interactions.