Continuously adjustable focus n-fractal aperiodic zone plate and its construction method

Abstract

The invention discloses an n-fractal aperiodic wave zone plate with continuously-adjustable focal points and a construction method thereof. The wave zone plate is formed by alternately arranging transparent annuluses and opaque annuluses according to an n-fractal binary aperiodic sequence; the n-fractal binary aperiodic sequence comprises n fractal sections, and the n fractal sections and each single fractal section are in the aperiodic sequence of the same type; the construction method comprises the steps of setting the n fractal sections in the aperiodic sequence of the same type, placing the aperiodic sequence into the n fractal sections, forming the n-fractal binary aperiodic sequence, and substituting the n-fractal binary aperiodic sequence into a transmittance function to construct the n-fractal aperiodic wave zone plate. The n-fractal aperiodic sequence is formed by constructing the n fractal sections, and each of the n fractal sections is composed of the aperiodic sequence of the same type, so that the first-level principal focus of the formed n-fractal aperiodic wave zone plate is continuously adjustable, imaging at any designated plane can be achieved conveniently, and axial dynamic operation particles, multi-plane fluorescent microscopy, photoetching and the like can be achieved in the three-dimensional space.

Description

technical field [0001] The invention relates to the field of optoelectronic technology, in particular to an n-fractal aperiodic zone plate with continuously adjustable focus and a construction method thereof. Background technique [0002] Since the introduction of aperiodic sequences into special diffractive optical elements, zone plates, aperiodic zone plates have found many special applications. Aperiodic zone plates with adjustable focus can focus light beams to target photolithography planes or focus light to arbitrary planes in the field of optical tweezers to trap particles. In addition, these zone plates can focus light onto the designed plane for sharper images. [0003] The Fresnel zone plate can axially generate the first-order principal focus at any position through the classical optical path difference method. Many methods have been proposed to make the aperiodic zone plate produce a position-adjustable primary focus. For example, the zone plate generated base...

AI Technical Summary

Problems solved by technology

[0004] The purpose of the present invention is to overcome the above-mentioned technical deficiencies, to propose an n-fractal aperiodic zone plate whose axial position of the focus can be continuously adjusted and its construction method, and to solve the problem that the axial main focus position of the zone plate cannot be continuously adjusted in the prior art technical problem

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