Diffractive optics opens unique possibilities
for beam shaping by redistribution of energy between the center and
periphery of the laser beam. The top-hat beam shapers are diffractive
optical elements used to transform a near-gaussian incident laser beam into
a uniform-intensity spot of either round or rectangular shape with sharp
edges. In order to gain a uniform-intensity light spot on a required plane
one just has to place a transparent diffractive optical element in the path
of the laser beam towards the spot. The diffractive pattern changes the
phase and as a result the intensity distribution changes within the spot.
The integral light transmittance of diffractive beam shapers ( 95~99%)
exceeds by far those of either slits-mask objectives or "gray-glass" bulky
lenses.
