Fig. 1. Schematic diagram of laser cleaning mechanism.

Fig. 2. Schematic diagram of experimental system.

Fig. 3. SEM image for breakdown threshold of silicon wafer.

Fig. 4. Confocal microscope images under different laser power densities: (a) 10 × 10⁷ W/cm²; (b) 8 × 10⁷ W/cm²; (c) 6 × 10⁷ W/cm².

Fig. 5. Time evolution features of LIBS from copper plate.

Fig. 6. LIBS experimental results of air and the sample.

Fig. 7. Delay time experimental results of sample 1: (a) delay time is 0−1 ms, (b) delay time is 0−30 ms.

Fig. 8. Experimental results of Cu particles with different concentrations when delay time was 1 ms: (a) 3D spectral intensity; (b) peak of spectral intensity.