Upconversion in fluoride glass fibers

Research News: Compact visible (blue) lasers are required for applications such as barcode reading, laser printing, and high‐definition optical recording. An alternative method to frequency doubling to obtain blue laser light is the up‐conversion of infrared light. In this process photons are converted to higher energies by generating high‐energy excited states in the energy level scheme of a rare‐earth ion which then emit at a higher frequency than that of the infrared excitation source.