A 1.55 μm laser gain medium based on Yb3+ and Er3+ co-doped KBa0.94Ca0.06Y(MoO4)3 crystal with in-situ operating temperature self-monitoring capability

Abstract

The 1.55 μm laser technology is widely applied in military, information communication, biomedicine and other fields. With the deepening development of these application areas, the demand for novel 1.55 μm laser gain media is becoming increasingly urgent. This study reports a novel Yb3+, Er3+ co-doped KBa0.94Ca0.06Y(MoO4)3 (KBCYM) crystal. In this crystal, Yb3+ serves as a sensitizer, significantly enhancing the emission intensity of Er3+ in both visible and near-infrared bands. Notably, when the concentration of Yb3+ reaches 6 mol%, the emission intensity peaks at 1.55 μm. Optical cross-section calculations reveal that the crystal exhibits a low laser pumping threshold at this concentration, demonstrating its potential as a laser gain medium. However, the crystal inevitably generates thermal effects during operation, which may adversely affect its performance. Therefore, real-time monitoring of the operating temperature is crucial. The thermal stability of the crystal was evaluated by measuring the temperature dependence of its luminescence intensity in the near-infrared band. Remarkably, even when the temperature rises to 553 K, the emission intensity at 1.55 μm only decreases by 10.9%. Additionally, the temperature sensing performance was evaluated using fluorescence intensity ratio techniques, yielding absolute and relative sensitivities of 0.00981 K–1 at 453 K and 1.32%/K at 303 K, respectively, highlighting its potential for optical temperature sensing. Finally, through leveraging the unique properties of Yb3+, Er3+: KBCYM crystals, we successfully developed 1.55 μm luminescent optical devices with practical applications. These devices not only exhibit efficient luminescent performance, but also possess a self-temperature measurement function, opening up new avenues for the further development of laser technology.