Jiafang Li

Neuromorphic vision systems demonstrate exceptional capabilities in spatial perception. However, identifying dynamic targets in complex environments often faces challenges from redundant background data, which imposes unnecessary computational overhead. Inspired by the frog retina's ability to suppress static backgrounds while detecting motion at the sensory level, we develop a multimodal vision sensor on a single 2D InSe platform. We fabricate asymmetric Schottky contacts within the device by a facile laser‐induced surface‐modification technique. This creates a strong built‐in electric field, enabling efficient self‐powered photodetection. Under an applied bias, defect‐mediated charge trapping facilitates an opto‐synaptic response. By switching between these two distinct modes, the InSe device functions as reconfigurable convolutional kernels, achieving high‐contrast spatial edge detection. Furthermore, this multimodal capability allows the sensors to isolate dynamic motion trajectories from redundant backgrounds, mimicking the frog's efficient visual processing. This work demonstrates a strategy for highly efficient motion perception in complex scenarios, and paves the way for developing low‐power and multi‐dimensional intelligent sensing systems.

Sodium has been proven to be a plasmonic material superior to noble metals. However, its high chemical reactivity poses a major obstacle to direct nanopatterning via conventional techniques, hindering the pursuit of sodium metasurfaces that simultaneously deliver high coupling efficiency and high quality factor. In this work, we developed a nanocast sodium-argon metasurface by rapidly cooling liquid sodium on a polymethyl methacrylate nanomold. This metasurface supports high-Q plasmonic resonances with record-high performance, surpassing previously reported alkali metal plasmonic systems. The liquid sodium consistently maintains an ultra-low filling depth regardless of the mold depth, which not only creates a nonlocal photonic configuration but also affords precise control over the radiative-to-dissipative loss ratio. Such casting behavior enables the metasurface to transition from under-coupling to critical-coupling regimes, thereby achieving high-efficiency, tunable second harmonic generation. We further provide direct experimental evidence that sodium outperforms silver in nonlinear optical performance. By leveraging the robustness inherent to the nonlocal nanocasting technique for sodium-argon metasurfaces, we demonstrate a large-area second harmonic generation metasurface with polarization-switchable imaging. The proposed sodium nanocasting technique opens an alternative avenue for sustainable high-performance plasmonics.

In stark contrast with traditional refraction phenomenon in isotropic media, refraction of hyperbolic polaritons enables extreme confinement and nanofocusing of mid-infrared light. However, the tuning of hyperbolic refraction typically relies on plasmonic systems (e.g., gating graphene and phase-change materials), and therefore, the electron–electron scattering introduces inevitable propagation losses of polaritons. Herein, we demonstrate that refraction of highly confined hyperbolic polaritons in α-phase molybdenum trioxide (α-MoO3) crystal strongly depends on the dielectric superstrate. We theoretically and experimentally indicate that both the wavevector (its direction and magnitude) and the propagation direction of refracted hyperbolic polaritons can be controlled by varying the twist angle between the vdW dielectric layers of tungsten diselenide (WSe2) and α-MoO3 crystals. Moreover, we observe the total internal reflection and zero-phase propagation of nanoscale-confined polaritons in hyperbolic media. Our study of the propagation of hyperbolic polaritons not only deepens the understanding of polariton refraction at the nanoscale and in strongly anisotropic media but also promises the development of functional nanophotonic elements and devices.

Realizing low-loss circular dichroism (CD) tuning and reversal is highly desirable for diverse applications, such as chiral sensing and optical encryption. Here, we demonstrate a strategy for achieving near-unity and high-Q CD reversal by manipulating chiral guided mode resonance (GMR) in planar dielectric metasurfaces. By simply rotating the etching curves around the center, the CD of the GMR can be continuously tuned from −0.996 to +0.754 at a fixed wavelength. More notably, by translating the curves, a near-unity normalized CD reversal from −0.996 to +0.985 is achieved, while the Q factor of GMR consistently exceeds 10 ³ . This reversal of chiral GMR excitation originates from the modulation of the phase difference between the GMR fields excited by two orthogonal linearly polarized components, which interchanges constructive and destructive interferences under opposite circularly polarized light incidence. Finally, the refractive index sensing performance of the chiral GMR and quasi-bound state in the continuum modes is investigated, demonstrating comparable sensitivities and high-Q CD resonances. By enabling CD sign reversal through phase-difference-controlled spin-selective interference rather than geometric chirality inversion, the chiral GMR provides a promising route for low-loss manipulation of chiroptical responses.

Optical tweezers (OT), a cornerstone of micromanipulation, are fundamentally constrained by substrate-induced adhesion and friction, limiting their application to mesoscale objects and fragile biological specimens where overcoming these resistive forces requires physiologically damaging laser powers. Here, we overcome this long-standing challenge by introducing dielectric levitation optical tweezers (DL-OT), a multiphysics platform that seamlessly integrates alternating-current dielectric levitation with optical traps. By using negative dielectrophoresis (n-DEP) to actively neutralize the normal force, DL-OT eliminates solid – solid contact and near-wall viscous drag. Crucially, we demonstrate the fundamental superiority of this active physical levitation over traditional passive antiadhesion coatings. This physical decoupling enables the smooth translation of large biological samples using low, biologically safe optical powers (~15 mW) rather than nonviable levels (>150 mW). The creation of this frictionless environment not only boosts the maximum manipulation speed of standard microtargets by 40% but also enables the stable optical transport of previously intractable mesoscale objects (100 to 260 μm), including microgears and shrimp eggs. By preventing photothermal damage and mechanical deformation, DL-OT demonstrates very good biocompatibility, significantly enhancing cell viability postmanipulation. Building upon these advantages, we demonstrate advanced on-chip biofabrication protocols through the targeted, high-precision assembly of multicellular spheroids and the safe transport of patient-derived organoids, followed by their success in situ culture. By transforming OT from a microscale tool into a mesoscale assembly platform, DL-OT paves the way for breakthroughs in tissue engineering, regenerative medicine, and the bottom – up assembly of living systems.

Pixel‐programmable miniaturized optical arrays with large pixel count are essential for cutting‐edge fields such as micro‐displays, photonic chips, and light detection modules. In recent advances, a universal strategy with ultrahigh pixel count and highly flexible programmability remains lacking. Here we report a programmable optical nano‐kirigami matrix with pixelated electromechanical reconfigurations. Deformable pixel arrays with high duty cycle and optical contrast are conceptually designed and experimentally realized based on a suspended turn‐shaped nano‐kirigami configuration. By employing the central plate to induce electrostatic force and the deformed arms to scatter incident light, switchable optical encryption and reconfigurable information display are demonstrated by programing the nano‐kirigami matrices with a pitch size of only a few micrometers. Furthermore, line‐level modulation based programmable information transmission and light projection are achieved by using a stripe‐shaped addressable nano‐kirigami matrix with 3.87 megapixels, showcasing an optical micro‐array with large pixel count and flexible programmability. Our work enables the high visibility and precise addressability of freely controllable electromechanical arrays with massive pixels, which could greatly improve the practical applicability for miniaturized optical arrays and brings potential applications in micro‐displays, photoelectronic chips, intelligent machine visions, hyperspectral image sensors, etc.

Dynamic modulation of infrared optical properties has significant importance for thermal imaging, molecular sensing, and communications. However, conventional dynamic metasurfaces, which rely on integrating functional materials such as phase-change materials or liquid crystals, face challenges such as complex fabrication, limited modulation range, and slow response speed. Here, the dynamic tuning of dual-band infrared resonances is demonstrated by reversibly deforming plasmonic slits in electrically reconfigurable nano-kirigami structures. The structural design adopts an Au–SiO ₂ –Si layered configuration, enabling reversible transformation from 2D planar patterns to 3D morphologies via electrostatic actuation. The pre-designed 2D patterns support dual-band plasmonic slit resonances, whose resonance wavelengths and intensities can be precisely controlled by geometric parameters. Under applied voltage, the structure undergoes controllable out-of-plane deformation, which breaks the in-plane symmetry of the plasmonic slits and modifies their effective length, width, and height. This enables dynamic, continuous, and reversible tuning of both the resonance intensity and wavelength. Simulations and experimental results confirm the prominent dual-band resonance responses, as well as the significant reconfiguration. Our work offers a new strategy for high-performance, easily integrable, and dynamically tunable infrared photonic devices, with potential applications in infrared sensing, spectral modulation, and adaptive optical systems.

Crystalline phases of transition-metal dichalcogenides offer unique structural configurations and tunable properties, driving phase engineering toward advanced fundamental and applied research. While strain is a recognized driver for modulating phase evolution, achieving spatially precise control over phase transitions remains a significant challenge. In this work, we present a lithography-compatible technique to modulate the phase evolution of TaS₂ flakes by using patterned Al₂O₃ nanofilm stressors. By employing standard photolithography and lift-off processes, exfoliated 1T-TaS₂ flakes were integrated with controllable patterned Al₂O₃ overlayers. Through a combination of on-chip comparative Raman spectroscopy and cross-sectional scanning transmission electron microscopy, we demonstrate that the strain induced by the Al₂O₃ stressor is the governing factor in modulating TaS₂ phase evolution with a thickness-dependent mechanical response. Our work provides a facile and scalable platform for spatially precise strain engineering to modulate phase transitions in transition-metal dichalcogenides toward the fabrication of phase-engineered structures in future nanoelectronic studies.