The calculation, fabrication and verification of diffraction grating based on laser beam splitters employing a white light scatterometry technique

In this work we present an application of polarized white light transmission and reflection measurements as well as simulation results for the analysis of diffractive optical elements, i.e. two port beam splitters for visible wavelength range lasers. A different pitch of 2, 4μm and a line height of 400–800nm phase diffraction gratings were fabricated in fused quartz substrates employing contact lithography and plasma chemical etching. Line heights of the beam splitters targeted for 405–633nm wavelength lasers were selected according to a straightforward analytical method. The resulting beam splitters were analyzed performing angular polarized white light reflection and transmission spectra measurements illuminating an 0.7cm2 area of the sample. Varying the surface profile in the “PCGrate” and “GSolver” simulation software and comparing the estimated transmission and reflection spectra with the experimental ones we have deduced the actual profiles of the structures. The assessed geometrical parameters of the profile, i.e. line height, groove and ridge widths correspond to the ones obtained when employing scanning electron and atomic force microscopy. The proposed modeling and validation method appeared to be an appropriate tool in the control of production of beam splitters possessing more than 60% diffraction efficiencies. •Analytical rectangular diffraction grating spectra analysis method was developed.•Beams splitters of the targeted line heights possessed predicted optical properties.•Scattered white light measurements and simulations provides geometrical dimensions.•r2 between experimental and simulated transmission spectra reaches 0.99.•Geometrical parameters obtained employing SEM, AFM agrees with scatterometric ones.