Figure 4: Influence of excitation flunece (~50 ps laser pulses at 405 nm) on the PL intensity at 475 nm.

It represents the variations of the PL intensities of QDs on 100-nm thick Si3N4/Ag (blue squares) and of QDs on 30-nm thick Si3N4/Ag (red triangles) with increasing fluence, respectively. Their relative intensity ratio defines the enhancement ratio indicated by the open circles.