Scattered complex-amplitude pupil filter for generating overlong light tube field

Abstract

The invention discloses a scattered complex-amplitude pupil filter for generating an overlong light tube field, comprising a plurality of scattered concentric multi-ring wave zone plates in circular symmetry, wherein main transmitting ring zones and cut-off ring zones are sequentially and alternately arranged outwards along a radius direction by taking a cut-off circular region with the transmittivity of 0 as the center of a cycle, the outmost ring is one of the main transmitting ring zones, the phase delays of all the main transmitting ring zones are changed in a pi and zero inverse alternation way along the radius direction, and the transmittivities of all the main transmitting ring zones are gradually increased from inside to outside along the radius direction. The pupil filter is suitable for an azimuthally-polarizing incident vector light field, and an overlong hollow light tube field can be obtained through modulating the complex amplitude of the incident light field and focusing a beam by using a large-numerical-aperture focusing system. The diffraction-limited light tube field is a pure azimuthally-polarizing vector light field, the lateral diameter of a light tube is smaller than a half of optical wavelength, and the axial length of the light tube can be up to several wavelengths, and the light tube field can be applied to the capture and control of nano-dimension particles.

Description

technical field [0001] The invention belongs to the technical field of vector diffractive optics, in particular a discretized, brand-new complex-amplitude pupil filter with dual degrees of freedom in the design of transmission amplitude and phase shift, which is used for large numerical aperture optical systems to detect incident angularly polarized vector beams Focusing can build a three-dimensional ultra-long vector light pipe field in the focusing field area. The vector light pipe field has important application value in optical particle trapping and manipulation. Background technique [0002] Space-variant polarized beam refers to a vector beam whose polarization state presents anisotropy or local dissimilarity distribution on the propagation section. Different from traditional polarized beams, such as linearly polarized or circularly polarized beams, this novel vector beam has unique photophysical properties and has attracted extensive attention from the international ...

AI Technical Summary

Problems solved by technology

However, due to the fixed incident light field mode used in this technology, only combined with phase regulation, the field quality of the "light needle" is restricted, and at the same time, the generation of other light fields with special focusing characteristics is limited.

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