Laser cleaning of micro-particles from a solid surface - Theory and applications

In laser cleaning of micro-particles from a solid surface, the adhesion force between the particles and the substrate surface, and the thermal expansion of both particles and substrate play important roles in determining the threshold laser fluence. Taking into account Van der Waals force and cleaning force due to fast thermal expansion of particles and substrate surface induced by pulsed laser irradiation, a cleaning model was established for the removal of tiny particles from substrate surfaces. The cleaning condition and cleaning threshold can be obtained from this model. This model can qualitatively and quantitatively predict the laser cleaning process depending on laser incident direction, laser wavelength, particle size, particle material and substrate material.