Blue upconversion luminescence for Yb3+/Tm3+ co-doped borosilicate glasses

A new kind of Yb3+/Tm3+ co-doped blue-emitting borosilicate glass was prepared by melting and quenching process. The Judd-Ofelt intensity parameters were calculated and discussed according to the recorded absorption spectrum. Strong blue upconversion emissions originated from the 1G4→3H6 transition of Tm3+ were observed under 980 nm excitation. It is suggested that the conversion of blue radiation is dominated by a three-photon absorption process. The optimized concentration of Yb3+ and Tm3+ was determined to be 0.6 mol% and 0.075 mol% based on the emission performance. The energy transfer process from Yb3+ to Tm3+ was analyzed and the energy transfer efficiency can reach up to 68%. The enhanced blue upconversion emission indicates that the Yb3+/Tm3+ co-doped borosilicate glass can be potential for applications of displays and blue lasers.