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Laser cleaning of optical surfaces of laser components

The technological process of laser head production involves cleaning the device parts from all kinds of contaminations. After the assembly of the device, the vacuum surfaces are inaccessible to cleaning by traditional methods, yet ten percent of optical components show contamination in the aperture zone after assembly. These contaminants are kept on the optical component surfaces by electrostatic forces which resist even strong vibrations and shocks. Various methods of surface cleaning with a laser beam are known from the literature, but all involve external surface cleaning. The present problem consists in performing the laser- induced cleaning of the precision optical surfaces in a vacuum, through the material of optical components, without inducing any changes in these optical components. The analysis of this problem, the spectral characteristics of optical component materials (fused silica, multilayer dielectric coating materials), and the spectral characteristics of potential contamination materials, has led us to the following conclusions: (1) the wavelength of processing radiation must satisfy the condition of optical component material transparency; (2) the intensity of processing radiation must be less than that of optical component damage threshold; (3) the radiation must be well absorbed by the contamination material; (4) the radiation wavelength must be as short as possible.