“Bulk crystal techniques confine infrared light to around 97% of its wavelength ... to MIT), but can also be thought of as sound energy. Both photons and phonons deal in the realm of excitations ...

by converting low-energy light into higher-energy wavelengths suitable for generating electricity. In regular photoluminescence, light hits a material and kicks an electron into a higher energy ...

This work reports the design of an efficient multiband UC system based on Ln3+/Yb3+-doped core-shell upconversion ...