High-efficiency super-surface vortex focusing lens

Abstract

The invention discloses a high-efficiency super-surface vortex focusing lens, and relates to the technical field of optical lenses. The lens comprises a substrate and a phase wavefront that is arranged on the substrate and has vortex focusing characteristics; the phase wavefront is composed of a plurality of nano-columns, and the corresponding phase values are given according to the position points of the nano-columns to convert the incident plane waves into vortex light having an arbitrary orbital angular momentum and focus the vortex light at a specified focal length; and a wavelength-scaleenergy ring is formed. Since the adopted theoretical mechanism can make full use of the incident light energy in addition to absorption and reflection, the size and distribution period of nano-antennas are also optimized, and point-by-point phase modulation is performed on a target wavefront rather than region-by-region phase modulation, so that the designed super-surface vortex lens can achieve afocusing efficiency of up to 80%, and the wavelength-scale high-energy vortex light can be formed.

Description

technical field [0001] The invention relates to the technical field of optical lenses, in particular to a high-efficiency metasurface vortex focusing lens. Background technique [0002] Traditional generation of complex vortex beams relies on bulky or expensive devices, such as spiral phase plates, computer-calculated holograms, subwavelength gratings, ring gratings, and amorphous media such as crystal liquids. So far, great progress has been made in the development of metasurface-based vortices, however, their phase realization mechanism largely depends on the cross-polarized components of the incident light, and the co-polarized components do not participate in the wavefront manipulation but Wasted, this design would theoretically result in an additional loss of total incident power, in addition to the usual losses such as absorption and reflection. In addition, the wavefronts of metasurfaces previously used to generate vortices are mostly adjusted region by region, which...

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Problems solved by technology

So far, great progress has been made in the development of metasurface-based vortices, however, their phase realization mechanism largely depends on the cross-polarized components of the incident light, and the co-polarized components do not participate in the wavefront manipulation but is wasted, this design theoretically results in an additional loss of total incident power in addition to the usual losses such as absorption and reflection

In addition, the wave fronts of the metasurfaces used to generate vortices were mostly adjusted region by region, which made the phase distribution in the azimuth angle very rough and uneven, resulting in low quality vortices.

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