Contactless temperature sensing via luminescence

Abstract

Sensitive detection of temperature in a non-contact fashion has applications in many diverse areas and disciplines. Immediate need exists for non-contact temperature measurement of moving or contact sensitive objects, hardly accessible bodies, or objects in hazardous locations. Materials and sensor platforms used for non-contact temperature measurements often limits their use in certain environments. The changes of luminescence properties of materials with temperature (such as changes of absolute and relative emission intensities, lifetime values of excited states, emission rise times, peak positions, and emission bandwidths) allow some materials to act as sensitive thermometers. The phenomenon become the basis of a new arm in the field of luminescence spectroscopy commonly termed as a luminescence thermometry. This lecture presents an overview of different modalities of luminescence thermometry, such as the use of materials with a single- or multi- emission centers, the selection of the reference emission, and advantages or disadvantages of the emission intensity measurements versus measurements of temporal changes in emission. Then, different classes of materials commonly utilized for luminescence thermometry are listed along with their figures of merit (temperature sensitivities, resolutions, measurement ranges. These include rare earth doped optical fibers, phosphors in forms of powders, thin films and ceramics, organic-inorganic hybrids etc. Finally, several state-of-the-art applications of remote temperature sensing with luminescence are shown.