Materials and devices using double-pumped-phosphors with energy transfer

The basic phenomena involved in double-pumped phosphors with energy transfer are described and discussed. The role played by successive multiple transfers as well as cooperative processes giving rise to antistokes fluorescence is emphasized for the different kinds of doping which have been used. The field of the different physical experiments is reviewed. Preparation of the most useful hosts is described and examples of applications are given as well as suggestions for future developments.