Fig. 1. (a) Photo of plasma-grating excited fluid jet stream. (b) Schematic of the spatial configuration of three filaments generated by pulses A, B, and C. The parallel structure represents plasma gratings generated by the nonlinear interactions of coplanar filaments A, B, and/or C. (c) Schematic of the top view of the plasma grating interacting with the fluid jet.

Fig. 2. Time evolution of a typical F-GIBS spectrum: evolution of (a) a typical F-GIBS with the detection delay and (b) the intensity and SNR of Cu I 324.7 nm excited by F-GIBS.

Fig. 3. F-GIBS signals of Cu I 324.7, Cr I 425.4, and Na I 588.9 nm attained under different interpulse delays.

Fig. 4. Top view of the noncollinear interaction area between pulses A and B to create plasma gratings (a) without and (b) with the third filament (pulse C) entering the plasma grating at 50 ps delay, respectively. The plasma grating fluorescence photos are shown in the inset pictures.

Fig. 5. Top view of the noncollinear interaction area between the ahead pulse C (−50ps delay) and plasma grating inducing by pulses A and B.

Fig. 6. Top view of the noncollinear coplanar filament interaction area as the three filaments are synchronized.

Fig. 7. Comparison of FIBS, GIBS, and F-GIBS at different delays (0 and ±50ps) in aqueous solutions for spectral lines of (a) Cu, (b) Cr, (c) H, and (d) Na elements.

Table 1. The enhancement factors of various spectral lines attained by GIBS and F-GIBS excitation protocols versus FIBS.