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Invisibility carpet cloaks are usually used to hide an object beneath carpet. In this paper we propose and demonstrate a carpet filter to hide objects and create illusions above the filter by using a Fourier optics method. Instead of using transformation optics, we get electromagnetic parameters of the filter by optical transfer functions, which play the(More)
We introduce and numerically demonstrate a kind of isotropic dielectric macroscopic cloaks for hiding objects and creating illusions at visible frequencies. The cloaks are designed by angular spectrum theory and their working principle is based upon time reversal and conjugation operation. We will demonstrate that the cloaks are capable of hiding both(More)
Owing to their strong photon emission, low excitonic binding energies, and nearly-ideal band offset values for water splitting reactions, direct gap quasi-2D gallium chalcogenides are potential candidates for applications in energy harvesting, optoelectronics, and photonics. Unlike other 2D materials systems, chemical functionalization of gallium(More)
We present a general insight into complementary medium-based camouflage devices from Fourier optics. The cloaks are simply spatial filters with different transfer functions and play the role of passively remedying or actively modulating the propagation optical field to make an object invisible or changeable. We further analytically show and numerically(More)
Invisibility devices have attracted considerable attentions in the last decade. In addition to invisibility cloaks, unidirectional invisibility systems such as carpet-like cloaks and parity-time symmetric structures are also inspiring some specific researching interests due to their relatively simplifying design. However, unidirectional invisibility systems(More)
The ability to noninvasive image through turbid media has long been a major scientific and technological goal in many disciplines. A breakthrough has been made to observe objects that were completely hidden behind an opaque scattering layer. However, such approach needs not only to scan both illumination light and detector but further off-line procedures to(More)
Realization of a perfect invisibility cloak still challenges the current fabricating technologies. Most experiments, if not all, are hence focused on carpet cloaks because of their relatively low requirements to material properties. Nevertheless, present invisibility carpets are used to hide beneath objects. Here, we report a carpet-like device to(More)
Quasi-two-dimensional gallium chalcogenide heterostructures are created by transferring exfoliated few-layer GaSe onto bulk GaTe sheets. Luminescence spectroscopy measurements reveal that the light emission from underlying GaTe layers drastically increases on heterojunction regions where GaSe layers make contact with the GaTe. Density functional theory(More)
A tunable nanosphere lithography (NSL) technique is combined with metal-assisted etching of silicon (Si) to fabricate ordered, high-aspect-ratio Si nanowires. Non-close-packed structures are directly prepared via shear-induced ordering of the nanospheres. The spacing between the nanospheres is independent of their diameters and tuned by changing the loading(More)
A new methodology to create 3D origami patterns out of Si nanomembranes using pre-stretched and pre-patterned polydimethylsiloxane substrates is reported. It is shown this approach is able to mimic paper-based origami patterns. The combination of origami-based microscale 3D architectures and stretchable devices will lead to a breakthrough on reconfigurable(More)