Generating asymmetric aberration laser beams with controlled intensity distribution

Abstract

We present generation of asymmetric aberration laser beams (aALBs) with controlled intensity distribution, using a diffractive optical element (DOE) involving phase asymmetry. The asymmetry in the phase distribution is introduced by shifting the coordinates in a complex plane. The results show that autofocusing properties of aALBs remain invariant with respect to the asymmetry parameters. However, a controlled variation in the phase asymmetry allows to control the spatial intensity distribution of aALBs. In an ideal ALB containing equal intensity bright lobes, by introducing asymmetry most of the intensity can be transferred to any one of single bright lobe, and forms a high-power density lobe. For a given beam parameter m, the precise spatial position of high-power density lobe can be controlled by the asymmetry parameter β, and we have determined the empirical relations for them. We have found that for the specific values of β, the intensity in the high-power density lobe can be enhanced by several times the intensity in other lobes. The experimental results show a good agreement with the numerical simulations. The findings can be suitable for applications such as in optical trapping and manipulation as well as material processing.