Enhanced 2.7- and 2.84-μm emissions from diode-pumped Ho³⁺/Er³⁺-doped fluoride glass

This work reports the intense emissions at 2.7 and 2.84 μm in a Ho³⁺/Er³⁺-codoped fluoride glass (ZrF₄-BaF₂-YF₃-AlF₃). An extensive transmission spectrum and the absence of strong OH⁻ absorption guarantee the observation of mid-infrared (IR) emissions. For the Ho³⁺/Er³⁺-codoped sample, the 2.7- and 2.84-μm emissions are 5.8 and 3.8 times higher with larger emission cross-sections (10.2×10⁻²¹ and 9.8×10⁻²¹ cm²), respectively. Meanwhile, other near to middle infrared emissions (1200, 2045 nm emissions from Ho³⁺ and 980, and 1535 nm emissions from Er³⁺ ions) are all enhanced. The collective enhanced effect originates from the disappearance of nonradiative decay processes after codping Er³⁺ and Ho³⁺ ions. Hence, the advantageous spectroscopic characteristics of Ho³⁺/Er³⁺-codoped ZBYA glass indicate that this kind of fluoride glass may be an attractive host to develop solid-state lasers for 3 μm.