The upconversion luminescence research of HoYb : YVO4

This paper studies the direct upconversion sensitization luminescence of the Ho3+ and Yb3+ ion codoped HoYb:YVO4 crystal excited by 960nm laser-diode initially. The interesting upconversion luminescence phenomenon has been found. The most strong upconversion luminescence line of the HoYb:YVO4 crystal is F-5(5)-->(5)Ig transition, and that of S-5(2) --> I-5(8) is ten times smaller relatively. It resulted from the fact that HoYb:YVO4 crystal has both strong oscillation strength and multiphonon nonraditive relaxation rate.