Multifunctional optical sensing platform of temperature, pressure (vacuum) and laser power density: NaYF4: Gd3+, Yb3+, Er3+ nanomaterial as luminescent thermometer, manometer and power meter

Abstract

Temperature and pressure are crucial physical parameters in materials science, hence their monitoring is especially important for scientists and engineers. Moreover, the on-target power density parameter is often underestimated, and in various real applications it is difficult to determine it correctly using conventional contact power meters. We developed for the first time, a multi-functional sensing platform allowing ratiometric optical detection of pressure (vacuum), temperature and excitation power density, using a sensor based on the upconverting inorganic nanomaterial (NaYF₄: Gd³⁺, Yb³⁺, Er³⁺) emitting in the visible range upon NIR laser excitation. The monotonic dependency between the temperature and the luminescence intensity ratio of the Er³⁺ thermally-coupled levels (TCLs), i.e. the intensity ratio of the band (525/550 nm), allows to monitor the temperature and laser-induced heating observed under vacuum conditions in the sample, so it is possible to use as a remote vacuum sensor. Moreover, the temperature elevation induced by increasing of the laser power also allows to use it as an optical power density meter. We believe that this work can inspire new research directions that will enable the development of the multi-functional sensor materials.