A simple and low-cost fiber-optic sensor based on photoluminescence for temperature independent ultraviolet detection

In this paper, we propose and experimentally demonstrate a simple and low-cost fiber-optic sensor for temperature-independent ultraviolet (UV) detection. The sensor utilizes a photosensitive material, i.e., acrylic and hydrogenated epoxy resin, which is tightly wrapped around one end of a multimode optical fiber (MMF) and processed by light curing and heat curing. Upon absorbing UV radiation, the phosphor in the resin compound undergoes population inversion, resulting in the emission band around 480 nm, and the peak intensity of the emission band is positively correlated with the UV excitation intensity. The UV sensing characteristics of the sensor are experimentally investigated by tracking the photoluminescence peak intensity of the output spectrum, demonstrating a fast response of 0.1-0.2 s, high sensitivity of 315.78 (mW/cm ² ) ^-1 , small absolute error within -0.28 to 0.42 mW/cm ² , and good repeatability (R>95%) and stability (RSD<1.3%). In addition, the peak intensity is proved to be insensitive to temperature variation: as temperature varies from -20.5 to 56.3 °C, it shows only a small fluctuation, RSD being less than 4.7%, indicating that the photothermal effects have negligible effect on the UV measurement accuracy. With the advantages of simple structure, easy fabrication, low cost and excellent performance, the proposed sensor is expected to be used for reliable UV detection in practical applications.