CVD diamond transmissive diffractive optics for CO2 lasers

Results of the development of CVD diamond transmissive diffractive optical elements (DOEs) for CO2 lasers an reported. The technique of laser ablation patterning of a diamond surface was applied to create a given phase microrelief on mechanically polished diamond plates. Micropatterning was performed using a KrF excimer laser (lambda=248 nm). Multilevel spherical (focal distanc of=100 mm) and cylindrical (f=25 mm) Fresnel lenses with an aperture up to 6x6 mm(2) were produced and tested. Using a cw CO2 laser as a probing beam, the intensity distribution in the focal plane and the focal depth of the lenses produced were measured, and these data are in good agreement with the results of calculations. The diffraction efficiency of the developed CVD diamond diffractive optical elements was found to be only 1-2% lower than the theoretical value.