Epitaxial growth of Er3+-doped CaF2 by molecular beam epitaxy

Monocrystalline Er3+-doped CaF2 layers are grown on CaF2 substrates by molecular beam epitaxy (MBE) with Er3+ concentration up to 31.2 wt%. The lattice parameter and the crystallinity of the epilayers are investigated by X-ray diffraction analysis, electron probe microanalysis, and scanning electron microscopy. Green light emission at 538 nm is generated by upconversion for the first time: using a 798 nm laser diode pump. Maximum emission intensity at this wavelength is obtained at an Er3+ concentration of 13.3 wt%.