Universal beam shaping technique for area processing of nanostructures in lattice IIFriday (26.06.2020) 09:50 - 10:10 Room 2
Beam shape is a key parameter in laser processing, and a flattop beam is in high demand in area processing. Under such background, various beam shaping methods such as diffractive optical element (DOE) and microlens array based beam homogenizer system have been developed. In addition, an adaptive beam shaping technique that uses vertical phase grating encoded on a spatial light modulator (SLM) with spatial frequency filtering in the Fourier plane in a 4f system was developed by Bagnoud in 2004. These methods have difficulties in flatness and edge steepness. To achieve beam shaping at high accuracy, we examined virtual diagonal phase grating in the adaptive beam shaping technique. This scheme spatially separates the residual and extracted components in the Fourier plane. As a result, efficient use of extracted component containing high spatial-frequency (HSF) component results in a highly uniform flattop beam of any cornered shape without ripples, suppressing the edge of the shaped beam to a width of 20 μm, which is less than 20 % of that obtained with conventional vertical phase grating. Our method, which allows for optimization of beam shaping by improving resolution and accuracy in the wide wavelength region from ultraviolet to near-infrared domain, will contribute to a wide field, including basic research, manufacturing and medical engineering.