Fluoride glasses: indium-based

Except for BeF2, glasses based on divalent fluorides show a broader IR transparency than glasses based on indium or zirconium, as reported for ZnSB and ZnSBC in Fig. 1 [10]. They exhibit a full transparency up to 9 /an for the former and 10 nm for the latter which is a pure MF2 fluoride glass containing Zn, Sr, Ba, and Cd. 

The optical properties of Pr3+ ions have been studied in various fluoride glasses based on zirconium [31,43,45-47], on indium [31,43,48,49] or on zinc fluorides [48,50]. 

Erbium ions in fluoride glasses possess several radiative transitions from the violet to the mid-IR (3.45 pm) as shown in Fig. 10. Their spectroscopic parameters such as radiative lifetimes and branching ratios were determined for several types of glasses based on zirconium, indium, aluminum or even zinc fluoride [31,98-100]. 

The (3H4 - 3F4 3H6 - 3F4) cross-relaxation is an efficient energy transfer mechanism for Tm3+ concentration greater than 0.1 mol% in indium-based fluoride glasses [124], Therefore, the intermediate 3F4 level can be populated not only by successive multiphonon relaxations from 3F3, but also through this cross-relaxation process [125],... 

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