RESUMO
The Pancharatnam-Berry (PB) phase can be used to control the phase of circularly polarized electromagnetic waves. However, there are few studies on the modulation of dual-circularly polarized multi-beam using the transmissive coding metasurface. A scheme of spin-controlling multi-beam by transmissive coding metasurface is proposed for dual-circular polarization simultaneously. The transmissive coding metasurface (TCMS) can transmit linearly polarized incidence into multi-beam with orthogonally circular polarization. The phase distribution is designed based the convolution theorem, and the elements of metasurface conforming to the PB phase are arranged according to the phase distribution. In order to compensate the emitting spherical waves into plane waves and realize the transmissive waves with dual-circular polarization, an interesting scheme of elements in different regions with different rotating phase are presented based on the principle of phase compensation. TCMS can transmit linearly polarized waves into two left-hand circularly polarized (LHCP) beams and two right-hand circularly polarized (RHCP) beams. The prototype of TCMS is fabricated and measured, and the experimental results agree well with the simulated data. The transmissive metasurface has potential application in holograms and satellite communication.
RESUMO
We provide several sharp upper and lower bounds for the generalized Euler-Mascheroni constant. As consequences, some previous bounds for the Euler-Mascheroni constant are improved.
RESUMO
A smart H-phosphonate-mediated synthetic strategy for the sulfonylation of heteroaromatic N-oxides has been developed, by which a large variety of 2-sulfonyl quinolines/pyridines were synthesized starting from easily available sulfonyl chlorides, diisopropyl H-phosphonate and pyridine/quinoline N-oxides in one pot under metal-free conditions at room temperature.
