Diffractive optical elements for laser marking applications

The interest of introducing diffractive optical components in industrial laser marking applications is presented. These components represent a new contribution of the optical micro-technology for the domain of the near infrared lasers having an average power of tens of watts. Optical functions ranging from gratings or dot matrices to complex modifications of the beam intensity distribution can be implemented. Automotive industry and industry in general is concerned by the identification of parts in a purpose of traceability. The applications include the marking on any kind of materials of bar codes, serial numbers, alphanumeric characters, logos, etc. This operation can be realized in one step at high cadences by direct marking thanks to the shaping of the laser beam. To optimize the quality of the shaping, fiber lasers which have a good beam quality factor are used. Laser parameters (energy density, exposure duration) required for the marking of two materials, polyamide and stainless steel, are investigated to demonstrate the feasibility of the process.