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

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) → 4A2(g) and 4T2(g) → 4A2(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.