Role of Focusing Distance in Picosecond Laser-Induced Cu Plasma Spectra

Figure 4

Graphs showing that the intensities of Cu atomic lines (i.e., Cu(I) at 324.75 nm, 327.40 nm, 510.55 nm, 515.32 nm, 521.82 nm, 570.02 nm, and 578.21 nm) change with , when using the lens L1 with a focus length of (a) 150 mm, (b) 100 mm, and (c) 50 mm. The pulse energy is 20 mJ.

(a)

(b)

(c)