Optical system and method for generating helical Bessel beam

Abstract

The invention discloses an optical system generating screw type Bessel beams and a generating method. The optical system is composed of a He-Ne laser device, a polarizer, a first beam expander, a binary amplitude grating, a second beam expander, an aperture diaphragm, a liquid crystal spatial light modulator, an axicon and a CCD camera. Gauss beams emitted from the He-Ne laser device are converted into 0-degree linearly polarized light after passing through the polarizer with a 0-degree polarizing direction, beam expanding is carried out on the 0-degree linearly polarized light through the first beam expander, the 0-degree linearly polarized light is vertically emitted into the binary amplitude grating, generated diffracted light passes through the second beam expander, the diffraction angles of all diffraction orders of the diffracted light are enlarged, single-ring Laguerre-Guss beams are obtained through the aperture diaphragm and are sent to the liquid crystal spatial light modulator, the Bessel beams which are off an axis and are transmitted around the axis in a screw mode are generated by passing through the axicon, and the Bessel beams are irradiated to the CCD camera to obtain light distribution. The optical system generating the screw type Bessel beams and the generating method achieve generation of the Bessel beams which are off the optical axis and are transmitted around the optical axis in the screw mode.

Description

technical field [0001] The invention relates to an optical system and a generating method for generating spiral Bessel beams, which can be widely used in the field of photoelectric technology. Background technique [0002] Bessel beams are a special set of solutions to the scalar wave equation in free space, whose light field distribution has the form of a Bessel function of the first kind. In 1987, J. Durnin first proposed the non-diffraction characteristics of Bessel beams, and called Bessel beams non-diffraction beams. An ideal Bessel beam would propagate without diffraction, without loss of energy, but this is impossible. The nearly non-diffracting Bessel beam can be realized by various experimental means. Such as annular slit-lens method, Mach-Zehnder interferometer method, axicon method, holographic optical method, etc. Bessel beams have important application prospects in the fields of micro-manufacturing, micro-nano optics, and optical tweezers, especially in the m...

AI Technical Summary

Problems solved by technology

[0004] The technical problem solved by the present invention is: to overcome the deficiencies of the prior art, provide an optical system and a generating method for generating a spiral Bessel beam, and solve the problem that the beam cannot be transmitted due to obstacles encountered during transmission

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