Near-infrared emission character of Tm³⁺-doped heavy metal tellurite glasses for optical amplifiers and 1.8 µm infrared laser

Abstract

Intense 1.8 µm and efficient 1.47 µm infrared emissions have been recorded in Tm3+-doped alkali–barium–bismuth–tellurite (LKBBT) glasses with lower phonon energies under the excitation of a 792 nm diode laser. The maximum emission cross-sections for the 1.8 and 1.47 µm emission bands are derived to be 6.643 × 10−21 and 3.551 × 10−21 cm2 and the peak values are obviously higher than those in Tm3+-doped ZBLAN fluoride and TBSN tellurite glasses, respectively. In low concentration doping, the full-widths at half-maximum (FWHMs) of the two emission bands are 206 nm and 109 nm, respectively, and peak intensity ratio between them is about 2. When the doping concentration increases to 1 wt%, the peak intensity ratio exceeds 7 and the quantum efficiency of 3H4 level is only 64.6% due to the cross-relaxation process [3H4, 3H6] → [3F4, 3F4], which benefits to achieve powerful 1.8 µm emission. The efficient and broad 1.8 and 1.47 µm infrared emission bands indicate that Tm3+-doped LKBBT glasses are suitable materials in developing S- and U-band amplifiers and 1.8 µm infrared laser.