Temperature Characteristics of the Green Up-Conversion Fluorescence of Er^{3 +}-Doped Gd₃Ga₅O₁₂ Single Crystal for Temperature Sensing

Temperature characteristics of 980-nm-upconverted green 530 and 550 nm emissions of Er^{3 +}-Doped Gd₃Ga₅O₁₂ single crystal have been studied for temperature sensing purposes. To this aim, a simple experimental setup has been developed that consists of a laser diode, two interference filters and two Si photocells, and does not use a monochromator or focusing lens for fluorescence collection. The study shows that the Er^{3 +}-Doped Gd₃Ga₅O₁₂ crystal displays stronger green upconversion fluorescence intensity (hence better signal-to-noise ratio) and higher temperature sensitivity of the fluorescence intensity ratio of the 530 to 550 nm emissions, which is (6.1–113.5) × 10^–3 K^–1 in the 100–430 K temperature range. These results indicate that the Er^{3 +}-Doped Gd₃Ga₅O₁₂ crystal is a promising material for optical temperature sensing.