Electrically Programmable Terahertz Diatomic Metamolecules for Chiral Optical Control

Abstract

Optical chirality is central to many industrial photonic technologies including enantiomer identification, ellipsometry-based tomography, and spin multiplexing in optical communications. However, a substantial chiral response requires a three-dimensional constituent, thereby making the morphology highly complex to realize structural reconfiguration. Moreover, an active reconfiguration demands intense dosage of external stimuli that pose a major limitation for on-chip integration. Here, we report a low bias, electrically programmable synthetic chiral paradigm with a remarkable reconfiguration among levorotatory, dextrorotatory, achiral, and racemic conformations. The switchable optical activity induced by the chiral conformations enables a transmission-type duplex spatial light modulator for terahertz single pixel imaging. The prototype delivers a new strategy towards reconfigurable stereoselective photonic applications and opens up avenues for on-chip programmable chiral devices with tremendous applications in biology, medicine, chemistry, and photonics.

Integrated Terahertz Generator-Manipulators Using Epsilon-near-Zero-Hybrid Nonlinear Metasurfaces

“…Over the last two decades, various methods have been developed for THz generation, such as those based on nonlinear organic crystals, , spintronic films, , topological materials, , and resonance-enhanced photoconductive antennas . Recent progress in metasurfaces has allowed for effective control of polarization and wavefront of terahertz waves. − However, in most THz systems demonstrated thus far, devices for generating and manipulating THz waves are spatially separated, while integrating these two essential functions into a single device, i.e., an integrated generator-manipulator (IGM), will lead to lower-cost and more-compact THz systems. This will significantly advance the current THz devices and technologies.…”

Terahertz Metamaterials for Free-Space and on-Chip Applications: From Active Metadevices to Topological Photonic Crystals

“…Although such a pneumatic drive configuration works well with a large deformation, it is difficult to be integrated into miniatured systems. A very simple L-shaped bimorph cantilevers were then proposed that could also provide a large chirality with electrostatic force actuation so that it could be easily integrated into a miniatured system [65]. The residual stress provides a gradient force that drives the L-shaped structure to form a three-dimensional half-spiral with intrinsic chirality.…”

Tunable Toroidal Response in a Reconfigurable Terahertz Metamaterial

“…[1] However, TDs have long been neglected since their radiation patterns are similar to electric dipoles (EDs) and are weak and uncommon in natural or microsystems, [32,33] provide a powerful platform to manipulate the effective properties of metamaterials and enable adaptive and multifunctional responses. For example, comb-drive electrostatic actuators and MEMS cantilevers can be used to modulate the resonance frequency, [34][35][36] polarization state, [37][38][39][40][41] amplitude, [42] and coupling coefficient [43] in metamaterials.…”