[Mid-infrared emission properties of Ho3+/Tm(3+)-codoped Ge-Ga-S-CsI glasses]

A serial of chalcogenide glasses based on 78GeS2-12Ga2S3-10CsI (in molar%) system doped with the different radios of Ho3+/Tm3+ ions were synthesized by melt-quenching method. Their absorption spectra and mid-infrared fluorescence under 808 nm laser excitation were measured. According to Judd-Ofelt theory, the intensity parameters omega(i) (i = 2, 4, 6), spontaneous transition probabilities A(rad) and radiative lifetomes tau(r) for Ho3+ ion were calculated. Absorption cross-sections sigma(a), emission cross-sections sigma(e) and gain coefficient G(lambda) corresponding to the emission of Ho3+ ions at 2.0 microm were obtained. By changing the Tm3+ concentration, the energy transfer regime of Tm3+ and Ho3+ ions under 808 nm excitation was investigated. The results show that Ho3+/Tm(3+)-codoped Ge-Ga-S-CsI glasses would be a potential material for 2.0 microm emission.