Beam profile flattener for Gaussian beams

Rotating shutters: a mechanical way of flattening gaussian beam profiles in time average

A mechanical method of flattening the Gaussian intensity distribution of laser beams in time average is presented. Specially shaped rotating shutters are the key feature of this method, which has been applied to achieve homogeneous submicrometer patterning of macroscopically large samples by laser interference exposure. This method represents a simple yet useful alternative to applying beam broadening or degaussing plates (apodizing filters).

Aberrated lenses for generating flattened laser irradiance

Expressions for describing Gaussian beams focused by a lens with spherical aberration have been derived. Numerical results show that, when the coefficient of the spherical aberration is negative, one can obtain flattened laser irradiance at two positions along the focused field. The larger the coefficient of negative spherical aberration, the larger the flatness is. The effect of the Fresnel number of the focusing lens on the flattened laser irradiance is also investigated.