Generation of shaped four-point pattern from splitting a flat-top laser beam

We report on the generation of shaped four-point pattern from splitting a flat-top laser beam using a diffractive optical element (DOE). It is very common to use a DOE to realize laser beam shaping and many algorithms, like Gerchber G-S axton (G-S) algorithm, have been studied. We employ the well-established modified G-S algorithm to design shaped four-point pattern with a novel approach, making use of input intensity interception and flat-top target setting to split a flat-top laser beam in a nearly smallest sampling number range. We demonstrate that the restricted condition of the approach is dependent on sampling number of output beam and the number range is discussed. The element of eight-level phase modulation is fabricated. In the experiment, the shaped four-point pattern is detected on the focal plane.