Advanced Materials

For the first time a freely tunable polarization rotator for broadband terahertz waves is demonstrated using a three-rotating-layer metallic grating structure, which can conveniently rotate the polarization of a linearly polarized terahertz wave to any desired direction with nearly perfect conversion efficiency. This low-cost, high-efficiency, and freely tunable device has potential applications as material analysis, wireless communication, and THz imaging.

Novel ultrathin dual-functional metalenses are proposed, fabricated, tested, and verified in microwave regime for the first time. The significance is that their anomalous transmission efficiency almost reaches the theoretical limit of 25%, showing a remarkable improvement compared to earlier ultrathin metasurface designs with less than 5% coupling efficiency. The planar metalens proposed in this paper empowers significant reduction in thickness, versatile focusing behavior, and high transmission efficiency simultaneously.

A process to surface pattern polydimethylsiloxane (PDMS) with ferromagnetic structures of varying sizes (micrometer to millimeter) and thicknesses (>70 μm) is developed. Their flexibility and magnetic reach are utilized to confer dynamic, additive properties to a variety of substrates, such as coverslips and Eppendorf tubes. It is found that these substrates can generate additional modes of magnetic droplet manipulation, and can tunably steer magnetic-cell organization.

A unique implementation of an organic image detector using resistive photo-switchable pixels is presented. A resistive photo-switch comprises the vertical integration of an organic photodiode and an organic resistive switching memory element. The photodiodes act as a photosensitive element while the resistive switching elements simultaneously store the detected light information.

The amplification of chirally modified, nonlinear signals from quantum emitters is demonstrated by manipulating the geometric chirality of resonant plasmonic nanostructures. The chiral center of the metamaterial is opened and emitters occupy this light-confining and chirally sensitive region. Nonlinear emission signals are enhanced by 40× that of the emitters not embedded in the metamaterial and display a 3× contrast for the opposite circular polarization.