Generation of multi-focus abruptly autofocusing beams with adjustable focus characteristics

This work introduces and demonstrates a method fir tailoring multi-focus abruptly autofocusing beams (MFAABs) in free space. Since MFAABs are formed by superposing the wavefronts of abruptly autofocusing beams (AABs), the number, positions, and relative intensity of foci are directly and independently adjusted during the pre-design of AABs. Also, we show that the size of the light field involves the characteristics of focus, such as peak intensity, focal size, and subsequent oscillations. We apply the double-phase hologram method to generate the required complex field with a phase-only spatial light modulator in experiments. With flexible control on foci characteristics, this work may broaden potential applications of autofocusing beams. (C) 2022 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement

Automated summary

This work introduces and demonstrates a method for tailoring multi-focus abruptly autofocusing beams in free space. It allows for direct and independent adjustment of the number, positions, and relative intensity of foci by controlling the design of abruptly autofocusing beams. The study also explores the relationship between the size of the light field and the characteristics of focus. By utilizing the double-phase hologram method, the required complex field is generated using a phase-only spatial light modulator in experiments, providing flexible control over the characteristics of foci and expanding potential applications of autofocusing beams.