Method for generating multi-focus self-focusing light beam with adjustable focus characteristic

Abstract

The invention discloses a method for generating a multi-focus self-focusing light beam with adjustable focus characteristics. The method comprises the following steps: constructing a self-focusing light beam through a caustics method; superposing wavefronts corresponding to the multiple groups of self-focusing light beams; coding the complex amplitude distribution of the wavefront into a pure phase form; the phase distribution obtained by loading the spatial light modulator is used for modulating an incident light field; and performing Fourier transform on the modulated light field by using a lens. The device has the beneficial effects that a light field can be converged to a plurality of focuses along different tracks after being modulated once, and regulation and control on the number and the position of the focuses and the relative intensity between the focuses can be realized at the same time, so that more flexible control on the energy of the light field is realized. According to the invention, the complex wavefront required for generating the multi-focus self-focusing light beam is coded into a pure phase form by using a biphase method, so that the requirement on light field regulation and control equipment is reduced.

Description

technical field [0001] The invention belongs to the technical field of light beam regulation, and in particular relates to a method for generating a multi-focus self-focusing light beam with adjustable focus characteristics. Background technique [0002] Since the Airy beam was experimentally generated and observed in 2007, this beam has attracted extensive attention from researchers due to its unique properties of transverse self-acceleration, non-diffraction propagation, and self-healing properties. In order to break through the limitation that Airy beams can only propagate along parabolic trajectories, the researchers proposed the optical caustics method, which enables the construction of self-accelerating beams propagating along arbitrary convex trajectories in real space or Fourier space. [0003] Research on self-accelerating beams has led to another class of beams with novel properties: sharply self-focusing beams. It was first proposed in 2010 and experimentally ver...

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Problems solved by technology

[0004] Aiming at the problem of how to generate a multi-focus self-focusing beam, Chinese Patent Publication No.: CN111522140A, application publication date: March 19, 2021, discloses a method for constructing a symmetrical multi-period cosine self-accelerating beam, which can be generated on the central axis Multiple focal points, but this method constructs a two-dimensional beam, the contrast of the generated focal point is not high, and the intensity and position of the focal point cannot be effectively controlled

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