Versatile Luminescence Thermometry via Intense Green Defect Emission from an Infrared-Pumped Fluorosilicate Optical Fiber

• Alexander Pietros, Kacper Rebeszko, Jacob Rosenbaum, Miranda Stone, Thomas Hawkins, Maxime Cavillon, John Ballato, and Peter Dragic
• received 12/26/2023; accepted 03/24/2024; posted 03/25/2024; Doc. ID 514785
• Abstract: An all-glass optical fiber capable of two distinct methods of optical thermometry isdescribed. Specifically, a silica-clad, barium fluorosilicate glass core fiber, when pumped inthe infrared, exhibits visibly intense green defect luminescence whose intensity and upper-statelifetime are strong functions of temperature. Intensity-based optical thermometry over the rangefrom 25°C to 130°C is demonstrated, while lifetime-based temperature sensitivity is shownfrom 25°C to 100°C. Time-domain measurements yielded a relative sensitivity of 2.85% K-1 at373 K (100C). A proof-of-concept distributed sensor system using a commercial digital single lens reflex camera is presented, resulting in a measured maximum relative sensitivity of 1.13%K-1 at 368 K (95C). The sensing system described herein stands as a new blueprint for defect based luminescence thermometry that takes advantage of pre-existing, and relativelyinexpensive, optical components and allows for the use of standard cameras or simply directhuman observation.