Figure 5

Time-dependent blue/green UC fluorescence intensity profiles of Tm3+ (a,b) and Er3+ (c,d) single-doped GCs under two-step excitation of one gating laser combined simultaneously with another C. W. laser with a fixed power. The rise time is defined as the time required from 10% to 90% of the output fluorescence, which can be recognized as non-steady state transition to steady state.