Method for controlling focus rotation by utilizing orthogonal polarized beam

Abstract

The invention relates to a method for controlling the focus rotation by utilizing an orthogonal polarized beam. The method is characterized in that an orthogonal polarized beam is used as the incidence light, wherein the beam is divided into two parts, one part of the beam is an inner ring beam, the other part of the beam is an outer ring beam, the inner ring beam and the outer ring beam are concentrically distributed, a polarization direction of the inner ring polarized light is vertical to that of the outer ring polarized light, a light spot which is formed by focusing the orthogonal polarized beam through a high-numerical-value aperture objective lens is of an elliptic shape, and the elliptic focus is rotated with the geometric focus as a center by adjusting the inner ring radius and the outer ring radius. Due to the method, the manual rotation of a half wave plate can be avoided, the rotation of the elliptic light spot can be realized, the shape of the orthogonal polarized light focus light spot is identical to that of the linear polarized light focus light spot, the deformation is avoided, the orthogonal beam is easy to produce, the applicability of the method is improved, and the flexibility and manipulability of an experiment also can be improved.

Description

technical field [0001] The invention relates to an applied optical technology, in particular to a method for controlling focus rotation by using orthogonal linearly polarized light beams. Background technique [0002] The light intensity distribution in the focal area has been a research hotspot because its nature greatly affects the performance of the optical system. With the increase of the numerical aperture of the objective lens, due to the increasing influence of the vector characteristics of the beam, it presents special properties in the focal area, and has been widely used in optical information storage, optical microscopy, lithography, laser processing, and optical micromanipulation. , super-resolution, light-matter interaction and other optical systems. [0003] In the study of super-resolution, how to obtain a circularly symmetrical spot with a small size is a difficult research point. In 1959, Wolf et al. found that the spot shape of linearly polarized light un...

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Problems solved by technology

If a circularly polarized beam is used for focusing, the spot shape is circular, but its size is larger than that of linearly polarized light, which is not conducive to the realization of super-resolution microscopy imaging

The study found that the focused spot size of radially polarized light is smaller than that of linearly polarized light, and the wavefront phase modulation of azimuthally polarized light is performed through a vortex phase plate with a topology of 1. The focused spot size is smaller than that of radially polarized light. Smaller, but because it is difficult to generate these two kinds of non-uniformly polarized beams, and the output beams of general commercial lasers are linearly polarized light, so the use of non-uniformly polarized beams as a method to achieve super-resolution has not been widely used

Recently, Seller et al. used linearly polarized light with a wavelength of 1580nm as the incident light. After bein

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