Fiber-optic temperature sensor based on embedded rare-earth luminescent nanoparticles

In this work, we report the fabrication and characterization of a fiber-optic temperature sensor based on embedding rare-earth nanoparticle emitters (NaYF4: Yb³⁺, Er³⁺) inside an optical fiber. A micro channel passing through the core of single mode fiber (SMF) is fabricated using a femtosecond laser, and the microcavity is subsequently filled with optically active medium. In this work, the NaYF4: Yb³⁺, Er³⁺ works as an active medium with temperature-sensitive upconversion luminescence properties to provide temperature measurements allowing for real-time temperature monitoring. The obtained results show promise for addressing temperature-related challenges in various fields, reaffirming the crucial role of optical sensors for a wide range of applications including industrial, medical, and environmental monitoring.