Manipulation and Improvement of Autofocusing Properties for Circular Butterfly Beams

Abstract

A new class of (2+1)‐dimensional circular butterfly beams (CBBs) is first demonstrated based on high‐dimensional butterfly catastrophes. The intensity of CBBs increases abruptly by two orders of magnitude right before they propagate to the focal plane, implying that they possess an abruptly autofocusing (AAF) ability induced by accelerating properties. The autofocusing performance can be further improved by introducing vortices. Owing to the flexibility of high‐dimensional catastrophes, butterfly beams exhibit diverse optical light structures; thus, the focal length, focal intensity, and light field structures of CBBs are tunable. Experimental results are consistent with numerical findings. Therefore, CBBs enrich the family of AAF beams and will be advantageous for optical micromachining, medical treatments, optical tweezers, and nonlinear processes.

Propagation property of the abruptly auto-focusing multi-focus beam

“…Focused beams can be used to manipulate small particles and improve the signal-to-noise ratio for free-space optical links [1,2]. Researches have shown that some beams have abrupt auto-focusing properties, such as circular Airy beams (CABs) [1,3], circle Pearcey beams [4,5], circle Olver beams [6], and so on [7][8][9]. It is worth mentioning that the CABs have attracted a lot of attention due to their auto-focusing property.…”