Main lobe shifting and splitting of 2D symmetric Airy beams via digital phase modulation.

Main lobe shifting and splitting phenomena of Airy beams are theoretically investigated based on the spatial light modulator (SLM) method. By digitally modulating the phase masks on the SLM, the single main lobe of the 2D symmetric Airy beam shifts to its neighboring side lobe. This results in the main-lobe splitting and the formation of a two-main-lobe state. These two main lobes further split into four while appropriately setting the phase modulation parameters. Meanwhile, the main lobe intensity decreases from 1.529 to 0.361 a.u. as the incident Gaussian beam's amplitude is 1. Therefore, one, two, or four main lobes can be obtained in Airy beams, and the corresponding intensity can be flexibly modulated by digital phase masks without moving the obstacle. Furthermore, a set of Airy beams with single main lobes and their corresponding splitting are realized by periodically setting the propagation distance. This further improves the modulation flexibility of the main lobe intensity. In our work, the number and intensity modulations of main lobes in Airy beams may have significant potentials for optical communication devices, such as tunable lasers and optical demultiplexers.