Multifunctional all-dielectric quarter-wave plate metasurfaces for generating focused vector beams of Bell-like states.

The generation of vector beams using metasurfaces is crucial for the manipulation of light fields and has significant application potential, ranging from classical physics to quantum science. This paper introduces a novel dielectric metasurface composed of quarter-wave plate (QWP) meta-atoms, known as a QWP metasurface, designed to generate focused vector beams (VBs) of Bell-like states under right circularly polarized illumination. The propagation phase imparted on both the co- and cross-polarized components of the output field constructs hyperbolic and helical phase profiles with topological charge , whereas the Pancharatnam-Berry (PB) phase acts only on the cross-polarized component to construct another helical phase profile with topological charge .

Metasurfaces for generating higher-order Poincaré beams by polarization-selective focusing and overall elimination of co-polarization components.

Focused higher-order Poincaré (HOP) beams are of particular interest because they facilitate understanding the exotic properties of structured light and their applications in classical physics and quantum information. However, generating focused HOP beams using metasurfaces is challenging. In this study, we proposed a metasurface design comprising two sets of metal nanoslits for generating coaxially focused HOP beams.

Generation of spatiotemporal optical vortices in ultrashort laser pulses using rotationally interleaved multispirals.

Ultrashort optical vortex pulses carrying spatiotemporal orbital angular momentum (OAM) have inspired versatile applications such as the micromachining of integrated quantum chips and discoveries such as optical toroidal structures and OAM-carrying X-waves. Generating high-quality ultrashort vortices with controllable topological charges remains a crucial issue. Thus, we propose a rotationally interleaved multispiral to generate such vortices.

Measurement of surface parameters from autocorrelation function of speckles in deep Fresnel region with microscopic imaging system.

The derived two-dimensional autocorrelation function of speckles in the deep Fresnel region shows that it is related to the scattering of rough surface with the scattered intensity profile acting as the aperture function. We propose the method that is convenient for measuring surface parameters from the normalized autocorrelation function of speckles acquired with a microscopic imaging system. In experiment, a multi-scale behavior of the speckles has been identified, which is compatible with fractal character.

Diffraction of a one-dimensional phase grating in the deep Fresnel field.

We analyze theoretically the diffraction of phase gratings in the deep Fresnel field on the basis of the theory of scalar diffraction and Green's theorem and present the general formula for the diffraction intensity of a one-dimensional sinusoidal phase grating. The numerical calculations show that in the deep Fresnel region the diffraction distribution can be described by designating three characteristic regions that are influenced by the parameters of the grating. The microlensing effect of the interface of the phase grating provides the corresponding explanation.