1.54 MU-M WAVELENGTH EMISSION OF HIGHLY ER-DOPED CAF2 LAYERS GROWN BY MOLECULAR-BEAM EPITAXY

CaF2:Er layers have been grown by molecular-beam epitaxy on (100)-oriented CaF2 substrates; the Er concentration ranges from 1% to 50% (mole fraction). The 1.54 mum emission observed under excitation around 800 nm was studied by photoluminescence. Up to 35% Er concentration the integrated emission increases monotonously, quenching appearing for higher doping levels. Photoluminescence results are discussed within the framework of previous studies of Er3+ emission in the near-infrared range (830-860 nm) in order to gain insight into the Er centers involved in the 1.54 mum emission.