Multifocal quasi-Fibonacci zone plate and construction method thereof

Abstract

The invention discloses a multifocal quasi-Fibonacci zone plate and a construction method thereof. The construction method comprises the steps of: acquiring a Fibonacci binary (A / B) aperiodic sequencebased on a recursion mode of Fibonacci numbers; and extending a recursion mode of the Fibonacci binary sequence to obtain a new recursion rule. According to the recursion rule, a new binary aperiodicsequence can be created, which is called a quasi-Fibonacci binary sequence. Based on the new sequence, the corresponding zone plate can be constructed by means of a transmittance function. The zone plate produces a series of focal points in the direction of an optical axis of an incident light beam, the focal points have the advantage of good polychromaticity, and imaging by means of the multifocal quasi-Fibonacci zone plate can reduce the color difference of the imaging; meanwhile, the multifocal quasi-Fibonacci zone plate has the plurality of focal points with relatively great intensities in the axial direction, can be used for binding and manipulating tiny objects, and can be used for constructing a three-dimensional optical trap array, so as to realize regular arrangement of particlesin a three-dimensional space.

Description

technical field [0001] The invention relates to the field of optoelectronic technology, in particular to a multi-focus Fibonacci-like zone plate and a construction method thereof. Background technique [0002] In photonics technology, diffractive optical elements are more flexible than geometric optical elements (such as: refracting prisms, pyramids, etc.). In addition, diffractive optical elements can also solve problems that traditional geometric optical elements cannot solve. A Fresnel zone plate composed of alternating transparent and opaque annular zones produces a principal focal point in the axial direction [Ref. 1]. This zone plate has very important applications in many scientific research fields, such as terahertz tomography[ References 2-4], Soft X-ray Microscopy [Refs 5-7], Photolithography [Refs 8], Optical Data Reading and Writing [Refs 9], Optical Tweezers [Refs 10-13 ]Wait. Although this traditional zone plate is still widely used, this type of zone plate ...

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Problems solved by technology

However, the intensity of the axial main focus of the Thue-Morse zone plate is relatively small, which has a certain impact on the stable capture of particles

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