We report a phenomenon of spectral anomalies in the interference field of Young's double-slit interference experiment. The potential applications of the spectral anomalies in the information encoding and information transmission in free space are also considered.
In this paper, a fully electronically reconfigurable reflectarray antenna that has 14×14 reflecting elements and features a higher aperture efficiency was designed, fabricated, and tested. A new configuration of the reflecting element was first developed so that all the bias circuit and the PIN diode are arranged on the opposite side of the reflecting surface, avoiding the potential unexpected reflection and aiming at the improvement of the antenna efficiency. The new reflecting element, which has a smaller size (0.365λ), was then applied to the design of a 14 × 14 reconfigurable reflectarray antenna. A field programmable gate array (FPGA)-based beam control system was also developed for the realization of an electronically beamscanning performance. The measurements of the prototype of the integrated reconfigurable reflectarray antenna show good beam-scanning radiation performance, a peak gain of 19.2 dBi, and an aperture efficiency of about 25%.
We study the focusing properties of a double-ring-shaped azimuthally polarized beam through an annular high NA objective lens. It is shown that a subwavelength focal hole (∼0.5λ) with a quite long depth of focus (∼26λ) is achieved near the focus. This kind of nondiffracting focal hole is called dark channel, which may have applications in atom optical experiments, such as with atomic lenses, atom traps, and atom switches.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.