Photon-avalanche for developing a high-sensitivity 3D-printed optical temperature sensor

Abstract

Photon avalanche (PA) is a phenomenon that generates intense emission under optical excitation in a weak absorption region of materials, particularly those doped with lanthanide ions such as thulium ions (Tm³⁺). Although PA behavior in various Tm³⁺-doped matrices has been previously investigated, this study proposes a different approach, i.e., using a different excitation wavelength (1060 nm) to observe and analyze the emission dynamics in order to focus its application as a highly sensitive temperature sensor in various media, such as air and isopropanol. LnF₃–ZnF₂–SrF₂–BaF₂–TmF₃ glass ceramic doped with Tm³⁺ was used to ensure the high effectiveness of the PA process and obtain intense emission. The choice of the glass ceramic also made it possible to prevent emission quenching in the proposed resin-based thermometer. Emission spectroscopy techniques were employed under varying excitation powers and temperatures to characterize the luminescence intensity ratio (LIR) and its correlation with temperature. The results demonstrate that the Tm³⁺-doped system exhibits avalanche behavior with relative sensitivities ranging from 0.01 to 4.9% K⁻¹ within the 299 to 354 K temperature range. Moreover, the uncertainty in temperature estimation remained low, between 0.67 and 0.32 K. These findings prove that Tm³⁺-doped glasses are promising candidates for developing precise and reliable optical sensors across various applications.