Intensity distribution of focussed laser beams in bio-medical studies

Abstract

Universal numerical solutions for the intensity of laser beams focussed by simple lenses having various amounts of primary spherical aberration have been obtained and are presented graphically in the form of lines of constant intensity (isophotes). The solutions demonstrate the increasingly non-uniform nature of the isophotes as the lens aberration function is increased. The existence of a multiplicity of intensity maxima, both along the optic axis and in off-axis positions, extending over comparatively large distances ( approximately mm) from the lens Gaussian focus, is disclosed. These must be taken into account in any quantitative assessment of the effects of laser beam radiation upon biological material.