High Sensitivity to Gamma Radiation of In-Fiber Long Period Gratings: Toward Dosimeters for Medical Applications

This work presents a highly sensitive optical fiber radiation sensing platform based on long period gratings (LPGs) inscribed in single-mode optical fibers doped with lutetium and aluminum (LuAG), as well as cerium. Following irradiation at different dose rates, the results demonstrate Gy sensitivity, partial permanence of radiation-induced effects, and excellent suitability for real-time in vivo dosimetry, underscoring the potential for medical radiation monitoring applications. Moreover, to understand re-use of this sensing platform, the long-term recovery behavior is investigated up to 24 months after irradiation, revealing the formation of permanent defects within the optical fiber materials.