We studied a two-dimensional square-lattice photonic crystal with all-angle negative refraction at its first band. Using this photonic crystal, we designed and fabricated a flat lens functioning as a cylindrical lens by increasing the vertical dimension of the photonic crystal. Two-dimensional finite-difference time-domain simulation validated negative refraction imaging. To perform the experim...

We report a quasi-flat and sub-wavelength acoustic lens built using soft matter process for broadband ultrasonic 3D focusing in water. By simple emulsion templating method, porous material with high index relative to water (∼5) has been molded shaped into convergent very low curvature thickness smaller than the working wavelength This kind of metasurface generates narrow focused beam, its focal...

The economic use of high-efficiency solar cells in photovoltaics requires high concentration of sunlight and therefore precise dual-axis tracking of the sun. Due to their size and bulkiness, these trackers are less adequate for small- to mid-scale installations like flat rooftops. Our approach to combine concentrating and tracking of sunlight utilizes two laterally moving lens arrays. The prese...