"If the emitted photon has more energy, the energy difference is called an anti-Stokes shift;[5] this extra energy comes from dissipation of thermal phonons in a crystal lattice, cooling the crystal in the process. Yttrium oxysulfide doped with gadolinium oxysulfide is a common industrial anti-Stokes pigment, absorbing in the near-infrared and emitting in the visible portion of the spectrum."https://en.wikipedia.org/wiki/Stokes_shift

If the emitted photon has more energy, the energy difference is called an anti-Stokes shift;[5] this extra energy comes from dissipation of thermal phonons in a crystal lattice, cooling the crystal in the process. Yttrium oxysulfide doped with gadolinium oxysulfide is a common industrial anti-Stokes pigment, absorbing in the near-infrared and emitting in the visible portion of the spectrum. (https://en.wikipedia.org/wiki/Stokes_shift)