Author(s): Haonan Chang, Jia-Min Lai, Feilong Song, Yanpei Lv, and Jun Zhang Optical refrigeration in semiconductors is driven by anti-Stokes photoluminescence (PL) arising from phonon-assisted up-conversion. In the conventional picture, lattice vibrations remain in thermal equilibrium and the relevant phonon population is pump independent, so the up-conversion rate scales a… [Phys. Rev. Lett. 137, 176902] Published Wed Oct 21, 2026