A device and method for generating fractional perfect vortex beam

Abstract

The invention relates to a generation device and generation method of a fractional-order perfect vortex beam. The device comprises a continuous wave laser; a light reflecting mirror is arranged at the advancing direction of a light beam emitted by the continuous wave laser; a pinhole filter, a convex lens I, a polarizer and a beam splitting cube are arranged at the advancing direction of a light beam reflected by the light reflecting mirror; a reflection spatial light modulator is arranged at the advancing direction of a light beam reflected by the beam splitting cube; a light beam reflected by the reflection spatial light modulator passes through the beam splitting cube; and an analyzer, a small-hole diaphragm, a convex lens II and a CCD camera are arranged at the advancing direction of the light beam that passes through the beam splitting cube. The generation method includes the following steps that: a computer is utilized to generate a light intensity pattern containing a cone lens transmittance function and fractional-order vortex beam and plane wave interference, and the light intensity pattern is written into the reflection spatial light modulator; and the power source of the continuous wave laser is switched on, and light is reflected in the device, and the reflected light is collimated, diffracted and reproduced, so that the fractional-order perfect vortex beam can be generated. With the generation device and generation method of the invention adopted, parameter real-time, online and free adjustable and controllable fractional-order perfect vortex beams can be realized. The generation device and generation method can be widely applied to fields such as particle optical manipulation and optical testing.

Description

technical field [0001] The invention relates to the field of particle light manipulation and optical testing, in particular to a device and method for generating a fractional order perfect vortex beam. Background technique [0002] Vortex beams have a wide range of applications in optical trapping and manipulation of tiny particles. It has become a very important research hotspot in the field of information optics in recent years. In 2004, M.V. Berry systematically and comprehensively expounded the theoretical basis of fractional optical vortex for the first time [J Opt a-Pure Appl Op, 2004, 62: 259]; subsequently, fractional vortex beams were verified experimentally [New J Phys, 2004, 61: 71]. Fractional vortex beams can carry more information and provide finer particle manipulation, which has become a hot topic for many researchers in the field of vortex optics. [0003] At present, there are many methods for generating vortex beams, mainly including mode conversion met...

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Problems solved by technology

In 2013, Andrey S. Ostrovsky and others proposed the concept of perfect vortex, the radius of the bright ring of the vortex beam does not depend on the topological charge value [Opt. Lett. 38, 5342013], but this method will be Generates additional stray aura

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