Upconverting nanoparticles typically absorb low frequency radiation and emit at higher frequencies relying upon multiphoton processes. One such type of particle is NaYF4:Yb. Er. which absorbs at 975 nm while emitting in visible radiation. https://www.ivoryjinelle.com/limited-value-Hunting-Camo-iPhone-SE-2nd-3rd-Gen-Pro-Case-p79729-hot-value/