• Bubs@lemm.ee
    link
    fedilink
    English
    arrow-up
    24
    ·
    3 days ago

    TL;DR from Wikipedia: In photon upconversion, two or more incident photons of relatively low energy are absorbed and converted into one emitted photon with higher energy.

    Basically photons are combined into a photon that is nearer in wavelength to visible light.