Wavelength Effects in the Laser Cleaning Process

The wavelength effects in the laser cleaning process were studied both theoretically and experimentally. As the reflectivity and absorption coefficient depend on laser wavelength, different wavelengths will result in different temperature distributions in a particle or a substrate so that various cleaning forces and efficiencies are induced in the laser cleaning process. For laser-induced removal of copper and aluminum particles from quartz surfaces, the cleaning efficiency is higher and the threshold fluence is smaller for a shorter wavelength under the same cleaning parameters. This is because laser irradiation at a shorter wavelength causes a higher temperature rise and induces a greater cleaning force in a copper or aluminum particle, which results in higher cleaning efficiency and lower threshold fluence. The theoretical analysis can successfully predict and explain the experimental results.