Excimer laser fabrication of low cost diffractive optical prototypes for CO2 laser marking applications.

We present a novel use of micro-machining with excimer laser : realization of reflective diffractive optical elements (DOE) for laser marking. The DOE's design is first calculated using the standard Gerchberg-Saxton algorithm associated with optimization procedures. The design takes into account the following parameters for the diffraction efficiency optimization : incident beam angle, M-2 quality factor and the modulation transfer function of the fabrication process. We consider here two phase levels elements in Fourier and Fresnel configurations. The fabrication process makes use of excimer laser ablation. We demonstrate the transfer of this design on different materials with two cases : direct and indirect substrate etching.