Generating asymmetric aberration laser beams with controlled intensity distribution

TL;DR

This paper demonstrates how to generate asymmetric aberration laser beams with controllable intensity distribution using a phase asymmetry introduced by a diffractive optical element, enabling precise control of high-power density lobes.

Contribution

The study introduces a method to control the intensity distribution of aberration laser beams through phase asymmetry, with empirical relations for positioning high-power lobes.

Findings

High-power density lobes can be achieved with 6 times the intensity of other lobes.

Auto-focusing properties remain invariant despite phase asymmetry.

Experimental results align well with numerical simulations.

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 auto-focusing 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 three bright lobes (for $m=3$), by introducing asymmetry most of the intensity can be transferred to any one of single bright lobe, and forms a high-power density lobe. A precise spatial position of high-power density lobe can be controlled by the asymmetry parameter $\beta$ and $m$, and we have determined the empirical relations for them. We have found that for the specific values of $\beta$, the intensity in the high-power density lobe can be enhanced by $\sim$6 times the intensity in other bright 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.