Optical heating and luminescence thermometry combined in a Cr3+-doped YAl3(BO3)4

Abstract

The possibility of optical heating with simultaneous control of the generated light within a single phosphor is particularly attractive from the perspective of multiple applications. This motivates the search for new solutions to enable efficient optical heating. In response to these requirements, based on the high absorption cross-section of Cr³⁺ ions, the optical heater based on YAl₃(BO₃)₄:Cr³⁺ exhibiting highly efficient heating is developed. At the same time, the emission intensity ratio of ²E_(g) → ⁴A_2(g) and ⁴T_2(g) → ⁴A_2(g) of Cr³⁺ bands, thanks to the monotonic temperature dependence, enables remote temperature readout of the phosphor using luminescence thermometry technique. The combination of these two functionalities within a single phosphor makes YAl₃(BO₃)₄:Cr³⁺ a promising, self thermally controlled photothermal agent.