Efficient Pr~(3+) Laser Material Excitation by Three-for-One Cross-Relaxation

摘要

Pr~(3+) has three excited manifolds with the right energy spacings for emission between 3.5 and 5.5 microns, and can be excited efficiently using laser diodes developed for telecommunications. In the potential laser crystal Pr:RbPb_2Cl_5, we have observed strikingly strong fluorescence in this wavelength range following 1.53-micron excitation. Careful analysis indicates this must be due to two cross-relaxation processes that, together, efficiently convert one Pr~(3+) initially excited to the ~3F_3 manifold into three ions excited to the ~3H_5 manifold. This newly discovered "three-for-one" cross-relaxation process in Pr~(3+) may greatly enhance its utility as a mid-infrared laser ion.