Laser-induced cavitation cleaning of micro–nanoparticles on optical glass: mechanisms and efficiency in aqueous environments

Abstract Laser cleaning of micro–nano particles is crucial for the maintenance of precision optical surfaces. This study explores a non-contact cleaning strategy that utilizes laser-induced water cavitation to remove CeO2 particles from the surface of K9 glass substrates. During the experiment, a 1064 nm, 12 ns pulsed laser beam was passed through the back of a transparent substrate to generate cavitation bubbles, which produced tangential shock waves when they collapsed. Experiments show that a laser energy of 180–240 mJ has a removal efficiency of over 90% with minimal substrate damage, and the surface morphology observed by scanning electron microscopy (SEM) indicates that there are rolling and sliding phenomena of particles. Research shows that the collapse of laser-induced cavitation bubbles generates strong tangential shock waves, causing the rolling removal of particles. Compared with the existing laser-based methods for removing micro–nano particles, it lowers the energy cleaning threshold and has a wider energy processing window. Furthermore, since this paper focuses on the particle cleaning of transparent substrates through the form of laser acting on the back and the laser energy used is relatively small, the damage caused to the front of the substrate is relatively small. The damage mainly comes from the rolling friction contact between the particles and the substrate.