Emission properties of 1.8 and 2.3 μm in Tm3+-doped fluoride glass

In this work a Tm3+-doped fluoride glass with good thermal stability is prepared. Intensive 1.8 and 2.3 μm emissions are obtained when pumped by an 800 nm laser diode. And the 1.48 μm emission is limited because of the much strong radiation around 1.8 μm. On the basis of absorption spectrum, radiative properties are investigated and discussed according to Judd–Ofelt parameters (Ω2, Ω4, Ω6) calculated by Judd–Ofelt theory. Besides, absorption and emission cross-sections of 3F4 → 3H6 transition are figured out and analyzed by using McCumber and Beer–Lambert theories. The high gain around 1.8 μm was predicted by the large σemiτrad product (29.8 × 10–21 cm2 ms). The results obtained indicate that the Tm3+-doped fluoride glass can be a promising 2.0 μm laser glass material.