Generation of Complex Transverse Energy Flow Distributions with Autofocusing Optical Vortex Beams

Abstract

Optical vortex (OV) beams are widely used for the generation of light fields with transverse energy flow inducing orbital motion of the nano- and microparticles in the transverse plane. Here, we present some new modifications of OV beams with autofocusing properties for shaping complex transverse energy flow distributions varying in space. The angular component of the complex amplitude of these beams is defined by the superpositions of OV beams with different topological charges. The proposed approach provides a convenient method to control the three-dimensional structure of the generated autofocusing OV beams. The control of the transverse distribution of an autofocusing beam provides a wide variety of generated fields with both rotating and periodic properties, which can be used in the field of laser manipulation and laser material processing. Thus, the obtained numerical results predict different types of motion of the trapped particles for the designed OV autofocusing beams. The experimental results agree with modeling results and demonstrate the principal possibility to shape such laser beams using spatial light modulators.

Mirror and Circular Symmetry of Autofocusing Beams

“…In particular, autofocusing beams acquire additional properties upon a vortex phase inserting [3,[53][54][55]. A more complex modification provides segmentation and complication of the beam structure [4,15,56,57], as well as rotation of a structured beam at propagation [58][59][60]. Another useful property of autofocusing beams is the possibility of forming optical bottles with complex shapes on their basis [61][62][63].…”

Recent Advances in Generation and Detection of Orbital Angular Momentum Optical Beams—A Review

“…In addition to SPPs, various DOEs (see Figure 3 ) are actively used to generate OVs, such as spiral axicons [ 81 , 82 , 83 ], generating Bessel beams of high orders, and spiral zone plates [ 84 , 85 , 86 ] which are a combination of a focusing lens and an SPP. Recently, unconventional focusing elements have been used to provide abruptly autofocusing [ 87 , 88 , 89 ]. The listed elements form OV beams on the optical axis.…”