Photon cascade emission and quantum efficiency of the 3P0 level in Pr3+-doped SrAl12O19 system

Photon cascade emission has been reported in Pr3+-doped SrAl12O19 system, providing a unique method for direct measuring the quantum efficiency of 3P0 in this material. The 1S0→1I6 fluorescence intensity can be taken as a measure of the initial 3P0 population. Thus the quantum efficiency of 3P0 can be calculated using the intensity ratio of the total emission from 3P0 and the emission of 1S0→1I6. The efficiency decreases as the concentration of Pr increases, indicating the effect of concentration quenching. The quantum efficiency is still substantially less than 100% even in dilute sample due to the thermal excitation of 1I6 and 3P1 states.