Fuli Zhang

Nonlocal resonances enabled by Brillouin zone folding in all-dielectric metasurfaces boost terahertz third-harmonic generation, which remains strong over wide incident angles, overcoming the angular sensitivity of conventional BICs.

Intelligent metasurfaces represent a pivotal advancement in dynamic holographic imaging, significantly enhancing holographic capacity. However, existing reconfigurable holographic systems are limited by factors such as low resolution and limited storage density, highlighting the necessity of innovative solutions. To address these limitations, we propose a holographic imaging scheme based on temporal integral holography (TIH), implemented with a 16×16 radiation-type metasurface controlled by a field-programmable gate array (FPGA) with embedded PIN diodes, operating without external feeding. The FPGA is programmed to generate discrete phase distributions that dynamically steer holographic focal points. Through temporal integration, these points accumulate to form a 5×5 focal array that serves as a basis for reconstructing arbitrary images. This scheme enables the flexible generation of diverse visual symbols on demand, including the complete set of letters, numbers, and symbols on a standard keyboard, thereby meeting the requirements for complex visual patterns and facilitating information transmission through the compact encoding of messages into customized spatial distributions. By eliminating the need for precomputed large-area phase profiles, the method could simplify system design and enhance flexibility. Simulations and experimental results demonstrate excellent agreement, confirming high-fidelity image reconstruction with minimal crosstalk. Overall, the proposed strategy offers a cost-effective, scalable solution for applications in intelligent sensing, next-generation wireless communications, and secure information encryption.

The coupling between closely spaced resonators as well as the resonant characteristics of metamaterials can effectively enhance the local fields, which can be employed for essential enhancement of nonlinear electromagnetic or optical resonance. Here, we demonstrate experimentally that the reinforced local field intensity can effectively enhance the nonlinear effect considering the coupling of a metamaterial made of asymmetric and nonlinear ceramic structure. Bistable behavior on the transmission is also demonstrated by modulating the input power. This study is promising for tunable meta-devices in practical applications considering the enhanced nonlinear light-matter interactions in dielectric metamaterials.

The development of terahertz (THz) sources with wide spectral coverage and dynamic control is critical for advancing high-speed communication, high-resolution imaging, and reconfigurable photonics. However, conventional nonlinear materials exhibit weak harmonic responses and limited tunability at room temperature. Here, we propose a nonlinear THz metasurface that simultaneously enables generation and optical modulation of both second and third harmonics with ultrafast switching speeds. The metasurface locally enhances THz magnetic and electric fields, which drive photoinduced carriers into anharmonic oscillations and produce harmonic emissions. Owing to the rapid excitations of free carriers, we achieve the modulation of SHG and THG with switching times of 4.31 ps and 3.98 ps, respectively, and their extinction ratios exceed 1000. Moreover, tuning the optical pump fluence enables amplitude modulation of harmonic outputs by dynamically manipulating carrier density and mobility. This single-device approach demonstrates a unified platform for generating, enhancing, and dynamically controlling multiple THz harmonics, offering new opportunities for reconfigurable THz sources and adaptive nonlinear photonic devices.

The increasing demand for electromagnetic (EM) spectrum dominance in modern electronic warfare has exposed the limitations of traditional jamming techniques, which often fail in emerging communication environments characterized by high adaptability, strong anti‐jamming capability, and parameter uncertainty. To address these challenges, a smart jamming approach based on a radiation‐type space‐time‐modulated metasurface (STMM) is proposed in this work. The STMM integrates 1‐bit phase shifting and radiation capabilities into a compact meta‐atom, enabling real‐time programmable modulation without external feed sources. By leveraging time modulation sequences, the proposed STMM adaptively generates in‐band aliased harmonic clusters that destructively jam target signals, even without prior knowledge of modulation formats or parameters. Additionally, spatial beam steering is achieved through precise control of the metasurface, enabling high‐energy aliased harmonic components to be directed toward multiple angular sectors, thereby realizing wide‐angle jamming coverage. The proposed jamming system is examined through a comprehensive framework comprising theoretical analysis, hardware prototyping, numerical simulations, and experimental validation. The results confirm that the capability of the proposed STMM to achieve intelligent, adaptive, and wide‐angle jamming. This work demonstrates a viable and highly efficient approach for novel smart jamming systems and provides a solid foundation for the development of advanced electronic countermeasure technologies.

Reducing mutual coupling between radiation elements of compact MIMO vehicle antennas is of fundamental importance to achieve simultaneous high capacity and miniaturization. In this work, we propose a commercial vehicle MIMO antenna composed of two inverted-F elements that achieves high isolation of mutual coupling through the incorporation of the electric split ring resonator (SRR). The working mode and frequency band of the SRR are rationally selected based on characteristic mode analysis (CMA). Experimental results validate high isolation below −20 dB across a broadband frequency range from 1.7 GHz to 2.7 GHz, achieving a relative bandwidth of 45.4%, with a maximum reduction of 15 dB of the S21 parameter. Additionally, the MIMO antenna maintains stable performance in both return loss and radiation characteristics, with minimal degradation in gain and radiation pattern. This work provides a compact and bandwidth-enhanced solution for vehicular communication systems.

Reconfigurable metamaterials significantly expand the application scenarios and operating frequency range of metamaterials, making them promising candidates for use in smart tunable device. Here, we propose and experimentally demonstrate that integrating metamaterial design principles with the intrinsic features of natural materials can engineer thermal smart metadevices. Tunable extraordinary optical transmission like (EOT-like) phenomena have been achieved in the microwave regime using shape memory alloy (SMA). The strongly localized fields generated by designed metadevices, combined with the intense interference of incident waves, enhance transmission through subwavelength apertures. Leveraging the temperature-responsive properties of SMA, the morphology of the metadevice can be recontructed, thereby modifying its response to electromagnetic waves. The experiments demonstrated control over the operating frequency and transmission amplitude of EOT-like behavior, achieving a maximum transmission enhancement factor of 126. Furthermore, the metadevices with modular design enable the realization of multiple functions with independent control have been demonstrated. The proposed SMA-based metamaterials offer advantages in terms of miniaturization, easy processing, and high design flexibility. They may have potential applications in microwave devices requiring temperature control, such as sensing and monitoring.

Polaritons in van der Waals (vdWs) materials enable light–matter interactions at the nanoscale. Polaritonic manipulation is of significance in fundamental physics and various promising nanophotonic applications. Here we study the asymmetric steering of phonon polaritons (PhPs) in hexagonal boron nitride (hBN) based on numerical simulations. Empowered by metagratings, the deflection angle of PhPs can be controlled. Furthermore, by employing the combination of metagrating and uniform grating, asymmetric steering of PhPs not only can be achieved but also can be switched to symmetric steering by tuning the period of grating. More intriguingly, an asymmetric dual-functional polaritonic metalens with the function of convergence/divergence for forward/backward incident PhPs is demonstrated. Our work provides insights into the manipulation of polaritons in vdWs materials and a promising strategy for developing nanophotonic devices.