Advanced control over the excitation of ultraconfined polaritons—hybrid light and matter waves—empowers unique opportunities for many nanophotonic functionalities, e.g., on-chip circuits, quantum information processing, and controlling thermal radiation. Recent work has shown that highly asymmetric polaritons are directly governed by asymmetries in crystal structures. Here, we experimentally demonstrate extremely asymmetric and unidirectional phonon polariton (PhP) excitation via directly patterning high-symmetry orthorhombic van der Waals (vdW) crystal α-MoO ₃ . This phenomenon results from symmetry breaking of momentum matching in polaritonic diffraction in vdW materials. We show that the propagation of PhPs can be versatile and robustly tailored via structural engineering, while PhPs in low-symmetry (e.g., monoclinic and triclinic) crystals are largely restricted by their naturally occurring permittivities. Our work synergizes grating diffraction phenomena with the extreme anisotropy of high-symmetry vdW materials, enabling unexpected control of infrared polaritons along different pathways and opening opportunities for applications ranging from on-chip photonics to directional heat dissipation.

Recently, Pancharatnam–Berry (PB) metasurfaces have exhibited powerful capabilities to control spin-polarized light. However, the adopted abrupt PB phase, introduced by simply rotating the basic elements, is spin-locked with opposite signs for different spin excitations, greatly limiting their practical applications. Here, we introduce a high-efficiency and broadband spin-unlocked metasurface with two mechanisms of a resonance phase and a geometric phase perfectly combined together. The design strategy is quite simple just through changing one geometric parameter rather than multi parameter optimization. As a proof of concept, the anomalous photonic spin Hall effect based on the spin-unlocked metasurface is demonstrated first, showing high experimental efficiency (over 80%) in a broad frequency range (11.3–16.6 GHz). Furthermore, another spin-unlocked metasurface is built to demonstrate the completely independent wavefront manipulations, i.e., the focusing effect and anomalous reflection. These findings significantly expand the electromagnetic control ability of a metasurface.

Optoelectronic synaptic transistors are attractive for applications in next-generation brain-like computation systems, especially for their visible-light operation and in-sensor computing capabilities. However, from a material perspective, it is difficult to build a device that meets expectations in terms of both its functions and power consumption, prompting the call for greater innovation in materials and device construction. In this study, we innovatively combined a novel perovskite carrier supply layer with an Al/MoO₃ interface carrier regulatory layer to fabricate optoelectronic synaptic devices, namely Al/MoO₃/CsFAMA/ITO transistors. The device could mimic a variety of biological synaptic functions and required ultralow-power consumption during operation with an ultrafast speed of >0.1 μs under an optical stimulus of about 3 fJ, which is equivalent to biological synapses. Moreover, Pavlovian conditioning and visual perception tasks could be implemented using the spike-number-dependent plasticity (SNDP) and spike-rate-dependent plasticity (SRDP). This study suggests that the proposed CsFAMA synapse with an Al/MoO₃ interface has the potential for ultralow-power neuromorphic information processing.

The polarization singularities in momentum space, rather than in real space, are capturing interest for active singular optics with exotic light scattering and various topological phenomena, which have potential applications in vortex nano-lasers, valley exciton emission, and others. Here, we propose to magnetically control the polarization singularities in momentum space in the photonic crystal slabs with inversion spatial symmetry (P symmetry). A pair of C points (circular polarization points) with the same topological charge is spawned from a V point (polarization vortex center), and they can be dynamically shifted in momentum space with the variation of the magnetic field. Moreover, the coupling between transverse electric (TE) and transverse magnetic (TM) modes induced by the magnetic field gives rise to a hybrid mode, which can close certain leaky channels to achieve an accidental V point. Such active manipulation of polarization singularities with magnetic field is promised for various applications in light–matter interactions and reveals novel phenomena and physics in singular optics and topological photonics.

This letter presents a novel dual-polarized millimeter-wave reconfigurable reflect-array antenna (RRA) with a cost-effective design. The proposed RRA element features two sets of orthogonal and rotationally symmetrical dipoles, each integrating only one p-i-n diode, which reduces the cost of active components and simplifies the layout of biasing circuits. By controlling the states of the corresponding-polarized diode, independent 1-bit phase shifts can be achieved for dual-linear polarizations. A 16 × 16-element RRA prototype is simulated, fabricated, and tested, with measurement and simulation results showing a good agreement. Both polarizations demonstrate independent 2-D beam scanning capabilities, with a maximum scanning angle of 50° and a gain drop of 3.1 dB. The maximum measured realized gains for x- and y-polarization are 19.4 dBi and 20.1 dBi, corresponding to aperture efficiencies of 13.3% and 15.7%, respectively.