Evaluation of the Fiber-Optic Thermometer Using Fluorescent Lifetime of Ruby

Abstract

Fiber-optic thermometer using photoluminescence lifetime from the spherical ruby crystal grown on the sapphire fiber has been fabricated using a new crystal growth process. Ruby sensor head with diameter from 0.5 mm to 6 mm have been grown on the sapphire fiber. We have optimized concentration of chromium (Cr³⁺) ion, size and shape of the ruby sensor head. From these results, red colored spherical ruby sensor head with Cr³⁺ concentration of 0.35 mol% was found to be the most suitable sensor head for fiber-optic temperature sensor. The temperature can be measured from 0 (C to 450 (C in the accuracy of (2 (C with rapid thermal response and good stability using this thermometer system.