Er3+-doped fluorotellurite glass microsphere lasers with ultra-low threshold

Er3+-doped tellurite glass microlasers have great potential in generating lasers in the communication band. However, the lasing threshold is generally high due to the influence of the hydroxyl groups of traditional tellurite glasses. In this work, we firstly demonstrate an Er3+-doped fluorotellurite glass microsphere laser with low lasing threshold. The lowest threshold power of 0.16 mW is experimentally obtained at similar to 1610 nm, which is approximately an order of magnitude lower than other Er3+-doped tellurite glass microlasers. Typical Q-factor of the fluorotellurite glass microspheres can reach 10(5). As the pump power increases, the single-mode and multimode lasers appear in the L- and C-bands successively. We also demonstrate that the microsphere lasers can be thermally tuned with a temperature sensitivity of 30 pm/degrees C. The experimental results indicate that the Er3+-doped fluorotellurite glass microsphere lasers can serve as a small photonic element in the new field of low-threshold, compact infrared laser sources and temperature sensing.