Generation of structured light beams with polarization variation along arbitrary spatial trajectories using tri-layer metasurfaces

Conventionally,the spatially structured light beams produced by metasurfaces primarily highlight the polarization modulation of the beams propagating along the optical axis or the beams'spatial transmission trajectory.In particular,along the optical axis,the polarization state is either constant or varies continuously in each output plane.Here,we develop innovative spatially structured light beams with continually changing polarization along any arbitrary spatial transmission trajectories.With tri-layer metallic metasurfaces,the geometric characteristics of each layer structure can be adjusted to modulate the phase and polarization state of the incident terahertz(THz)wave.The beam will converge to the predefined trajectory along several paths to generate a Bessel-like beam with longitudinal polarization changes.We demonstrate the versatility of the approach by designing two THz-band structured light beams with varying polarization states along the spatial helical transmission trajectory.Continuous linear polarization changes and linear polarization to right circular polarization(RCP)and back to linear polarization changes are realized respectively.The experimental results are basically consistent with the simulated results.Our proposal for arbitrary trajectory structured light beams with longitudinally varying polarization offers a practical method for continuously regulating the characteristics of spatial structured light beams with non-axial transmission.This technique has potential uses in optical encryption,particle manipulation,and biomedical imaging.

Intelligent control technology for deep drawing of sheet metal

The intelligent press forming of sheet metal is a completely new and comprehensive technology that combines control-science, computer science, material science and metal forming theory. Although the technology originated in 1980s from America, it was focused on the spring-back of V-shaped bending. Not until 1990s was some pioneering research conducted on the intellectualized control of cup-deep drawing. The research field is expanded to the axis-symmetric part and non-axis symmetric part. After a series of theoretical and experimental research, an intellectualized control system on the deep drawing processing of sheet metal is developed. The common general feature of sheet metal on the process of deep drawing is analyzed and a completely mechanical model is concluded and the deep drawing intellectualized control of sheet metal is finally realized.

Multiple Non-Axially Solutions to a Mean Field Equation on S^2

We study the following mean field equation■,whereρis a real parameter.We obtain the existence of multiple non-axially symmetric solutions bifurcating from u=0 at the valuesρ=4 n(n+1)πfor any odd integer n≥3.

Bubbling solutions of fourth order mean field equations on S^(4)

In this paper,we first establish the existence of blow-up solutions with two antipodal points of the fourth order mean field equations on S^(4).Moreover,we construct non-axially symmetric solutions with blow-up points at the vertices of regular configurations,i.e.,equilateral triangles on a great circle,regular tetrahedrons,cubes,octahedrons,icosahedrons and dodecahedrons.The bubbling rates of these blow-up solutions rely on various bubbling configurations.