Spectral Multiplexing of Rare‐Earth Emitters in a Co‐Doped Crystalline Membrane (Advanced Optical Materials 15/2024)

Spectral Multiplexing of Rare-Earth Emitters Individual erbium dopant atoms (yellow) in crystals made from other elements can be detected by measuring fluorescence light after resonant excitation with a laser. When the dopants are located at a site that is neighboring another dopant atom (blue), the resonance frequency is changed because of the mutual interaction. This allows one to tailor the spectral distribution of the emitters even at very low concentrations, such that correspondingly co-doped crystals can be better used for quantum information applications. For further details, see article number 2302897 by Andreas Reiserer and co-workers. [Cover image by C. Hohmann, MCQST.]