Multiple primary aberrations effect on donut-shaped laser beam in high NA focusing system

A donut-shaped laser that is simultaneously impacted by the coma, astigmatism and spherical aberrations in a high NA focusing system is numerically simulated based on the vectorial diffraction theory. The full-width half-maximum, intensity characters, and dimensions of the dark cores of the donut-shaped laser on the focal plane are quantitatively analyzed. The results are highly consistent with the annular-shaped nano-patterns that are experimentally fabricated by our purpose-built laser direct writing system. The mechanism of asymmetric nano-patterns fabricated through laser writing lithography is also revealed. (paper)