Enhanced green and red upconversion and 2.7 μm emission from Er3+/Tm3+ co-doped bismuth germanate glass

This work studied the spectroscopic properties of Er3+/Tm3+ co-doped bismuth germanate glass. Through Tm3+ co-doping and 980 nm LD pumping, the enhanced green (2H11/2, 4S3/2→4I15/2) and red (4F9/2→4I15/2) upconversion emission as well as 2.7 μm emission (4I11/2→4I13/2) of Er3+ ions were observed. Meanwhile, the 1.5 μm emission (Er3+:4I13/2→4I15/2) is significantly suppressed. Broadband 1.8 μm emission (Tm3+:3F4→3H6) is got. The luminescent characteristics and dominant energy transfer mechanisms between Er3+ and Tm3+ ions are investigated. The emission cross section at 2.7 μm of this glass is found to be as high as 1.10 × 10−20 cm2. Therefore, the spectroscopic characteristics of Er3+/Tm3+ co-doped bismuth germanate glass indicate it is a potential active medium for optical upconversion and mid-infrared luminescence devices.

► An Er3+/Tm3+ codoped bismuth germanate glass is synthesized.
► The enhanced green and red upconversion emissions are observed.
► The emission cross section at 2.7 μm reaches 1.10 × 10−20 cm2.
► The energy transfer mechanism between Er3+ and Tm3+ is discussed.