Longitudinally continuous varying high-order cylindrical vector fields enabled by spin-decoupled metasurfaces.

The manipulation of vector optical fields in three-dimensional (3D) space plays a vital role in both fundamental research and practical implementations of polarization optics. However, existing studies mostly focus on 3D vector optical fields with limited modes. Here, an approach of spin-decoupled spatial partitioning is proposed to generate complex 3D vector optical fields with a customizable number of modes on demand.

Dynamic nonlocal metasurface for multifunctional integration via phase-change materials.

Non-local metasurface supporting geometric phases at bound states in the continuum (BIC) simultaneously enables sharp spectral resonances and spatial wavefront shaping, thus providing a diversified optical platform for multifunctional devices. However, a static nonlocal metasurface cannot manipulate multiple degrees of freedom (DOFs), making it difficult to achieve multifunctional integration and be applied in different scenarios. Here, we presented and demonstrated phase-change non-local metasurfaces that can realize dynamic manipulation of multiple DOFs including resonant frequency, values, band, and spatial wavefront.

High-resolution non-line-of-sight imaging based on liquid crystal planar optical elements.

Non-line-of-sight (NLOS) imaging aims at recovering hidden objects located beyond the traditional line of sight, with potential applications in areas such as security monitoring, search and rescue, and autonomous driving. Conventionally, NLOS imaging requires raster scanning of laser pulses and collecting the reflected photons from a relay wall. High-time-resolution detectors obtain the flight time of photons undergoing multiple scattering for image reconstruction.

Continuous-wave degenerate cavity laser for optical imaging in scattering media.

Lasers play a significant role in optical communication, medical, and scientific research, owing to their high brightness and high coherence. However, the high spatial coherence will lead to specific challenges, such as speckle noise in imaging and wavefront distortion during propagation through scattering media. Here, a continuous-wave (cw) degenerate cavity laser (DCL) with low spatial coherence is demonstrated with efficient suppression of the thermal lensing effect from the gain crystal.

Monocular Metasurface for Structured Light Generation and 3D Imaging with a Large Field-of-View.

Structured light three-dimensional (3D) imaging technology captures the geometric information on 3D objects by recording waves reflected from the objects' surface. The projection angle and point number of the laser dots directly determine the field-of-view (FOV) and the resolution of the reconstructed image. Conventionally, diffractive optical elements with micrometer-scale pixel size have been used to generate laser dot arrays, leading to limited FOV and point number within the projection optical path.

Simultaneous Circular Dichroism and Wavefront Manipulation with Generalized Pancharatnam-Berry Phase Metasurfaces.

Simultaneous circular dichroism and wavefront manipulation have gained considerable attention in various applications, such as chiroptical spectroscopy, chiral imaging, sorting and detection of enantiomers, and quantum optics, which can improve the miniaturization and integration of the optical system. Typically, structures with n-fold rotational symmetry ( ≥ 3) are used to improve circular dichroism, as they induce stronger interactions between the electric and magnetic fields. However, manipulating the wavefront with these structures remains challenging because they are commonly considered isotropic and lack a geometric phase response in linear optics.

Ultra-thin sub-diffraction metalens with a wide field-of-view for UV focusing.

In recent years, wide field-of-view imaging technology based on a metasurface has been widely applied. However, works on the reported sub-diffraction metalens with a wide field-of-view indicate that multiple structures are essential to effectively eliminate aberrations, which results in a heavy device thickness and weakens the advantage of an ultra-thin metasurface. To solve this problem, according to the super-oscillation theory and the translational symmetry of quadratic phase, as well as the principle of virtual aperture diaphragm based on wave vector filter, this Letter demonstrates a sub-diffraction metalens combined with a single quadratic metalens and a wave vector filter.

Visible Meta-Displays for Anti-Counterfeiting with Printable Dielectric Metasurfaces.

Metasurfaces, 2D arrays of nanostructures, have gained significant attention in recent years due to their ability to manipulate light at the subwavelength scale. Their diverse applications range from advanced optical devices to sensing and imaging technologies. However, the mass production of dielectric metasurfaces with tailored properties for visible light has remained a challenge.

A Novel Multifunctional Photonic Film for Colored Passive Daytime Radiative Cooling and Energy Harvesting.

Passive daytime radiative cooling (PDRC) materials with sustainable energy harvesting capability is critical to concurrently reduce traditional cooling energy utilized for thermal comfort and transfer natural clean energies into electricity. Herein, a versatile photonic film (Ecoflex@BTO@UAFL) based on a novel fluorescent luminescence color passive radiative cooling with triboelectric and piezoelectric effect is developed by filling the dielectric BaTiO (BTO) nanoparticles and ultraviolet absorption fluorescent luminescence (UAFL) powder into the elastic Ecoflex matrix. Test results demonstrate that the Ecoflex@BTO@UAFL photonic film exhibits a maximum passive radiative cooling effect of ∽10.

Demonstration of 120 Gbit/s turbulence-resilient coherent optical communication employing cylindrical vector beam multiplexing.

Free space optical (FSO) communication has gained widespread attention due to its advantages, including high confidentiality, high communication capacity, and no limitation of spectrum. One of the great challenges in FSO communication is the transmission performance degradation in atmospheric turbulence channel due to wavefront distortion and scintillation. Here, we proposed and experimentally demonstrated a 120 Gbit/s vector beam multiplexed coherent optical communication system with turbulence-resilient capacity.

A Versatile Strategy for Concurrent Passive Daytime Radiative Cooling and Sustainable Energy Harvesting.

Developing versatile systems that can concurrently achieve energy saving and energy generation is critical to accelerate carbon neutrality. However, challenges on designing highly effective, large scale, and multifunctional photonic film hinder the concurrent combination of passive daytime radiative cooling (PDRC) and utilization of sustainable clean energies. Herein, a versatile scalable photonic film (Ecoflex@h-BN) with washable property and excellent mechanical stability is developed by combining the excellent scattering efficiency of the hexagonal boron nitride (h-BN) nanoplates with the high infrared emissivity and ideal triboelectric negative property of the Ecoflex matrix.

Flexible long-wave infrared snapshot multispectral imaging with a pixel-level spectral filter array.

This paper proposes and demonstrates a flexible long-wave infrared snapshot multispectral imaging system consisting of a simple re-imaging system and a pixel-level spectral filter array. A six-band multispectral image in the spectral range of 8-12 µm with full width at half maximum of about 0.7 µm each band is acquired in the experiment.

High-efficiency amplitude and phase control of infrared light using topological polaritons.

Polaritons - material excitation coupled with light - are thought to hold the potential for the extreme control of light down to the atomic length scale because of their high field confinement and sub-wavelength scales. For practical applications, it is essential but still a formidable challenge to manipulate polaritons with high efficiency and a wide tunable range. These obstacles may be overcome by the topology of polaritons.

Miniaturized solar-blind ultraviolet imaging system enabled by a diffractive/refractive hybrid.

In this paper, we demonstrated a miniaturized diffractive/refractive hybrid system based on a diffractive optical element and three refractive lenses to achieve solar-blind ultraviolet imaging within a range of 240-280 nm. We experimentally demonstrate the optical system has both outstanding resolution and excellent imaging capability. The experiments demonstrate that the system could distinguish the smallest line pair with a width of 16.

Meta-optics empowered vector visual cryptography for high security and rapid decryption.

Optical encryption is a promising approach to protecting secret information owing to the advantages of low-power consumption, parallel, high-speed, and multi-dimensional processing capabilities. Nevertheless, conventional strategies generally suffer from bulky system volume, relatively low security level, redundant measurement, and/or requirement of digital decryption algorithms. Here, we propose a general optical security strategy dubbed meta-optics-empowered vector visual cryptography, which fully exploits the abundant degrees of freedom of light as well as the spatial dislocation as key parameters, significantly upgrading the security level.

Experimental demonstration of an 8-Gbit/s free-space secure optical communication link using all-optical chaos modulation.

For the first time, to the best of our knowledge, we experimentally demonstrate a high-speed free-space secure optical communication system based on all-optical chaos modulation. The effect of atmospheric turbulence on optical chaos synchronization is experimentally investigated via a hot air convection atmospheric turbulence simulator. It is shown that, even under moderately strong turbulent conditions, high-quality chaos synchronization could be obtained by increasing the transmission power.

Simple route for high-throughput fabrication of metasurfaces using one-step UV-curable resin printing.

Phase-gradient metasurfaces are two-dimensional (2D) optical elements that can manipulate light by imposing local, space-variant phase changes on an incident electromagnetic wave. These metasurfaces hold the potential and the promise to revolutionize photonics by providing ultrathin alternatives for a wide range of common optical elements such as bulky refractive optics, waveplates, polarizers, and axicons. However, the fabrication of state-of-the-art metasurfaces typically requires some time-consuming, expensive, and possibly hazardous processing steps.

High Performance Graphene-C -Bismuth Telluride-C -Graphene Nanometer Thin Film Phototransistor with Adjustable Positive and Negative Responses.

Graphene is a promising candidate for the next-generation infrared array image sensors at room temperature due to its high mobility, tunable energy band, wide band absorption, and compatibility with complementary metal oxide semiconductor process. However, it is difficult to simultaneously obtain ultrafast response time and ultrahigh responsivity, which limits the further improvement of graphene photoconductive devices. Here, a novel graphene/C /bismuth telluride/C /graphene vertical heterojunction phototransistor is proposed.

Meta-Optics-Empowered Switchable Integrated Mode Converter Based on the Adjoint Method.

Monolithic integrated mode converters with high integration are essential to photonic integrated circuits (PICs), and they are widely used in next-generation optical communications and complex quantum systems. It is expected that PICs will become more miniaturized, multifunctional, and intelligent with the development of micro/nano-technology. The increase in design space makes it difficult to realize high-performance device design based on traditional parameter sweeping or heuristic design, especially in the optimal design of reconfigurable PIC devices.

Optically transparent infrared selective emitter for visible-infrared compatible camouflage.

Visible-infrared compatible camouflage is significant to enhance the equipment survivability through counteracting the modern detecting and surveillance systems. However, there are still great challenges in simultaneously achieving multispectral camouflage with high transmittance in visible, low emissivity in the atmospheric windows and high emissivity in the non-atmospheric window, which can be attributed to the mutual influence and restriction within these characteristics. Here, we proposed an optically transparent infrared selective emitter (OTISE) composed of three Ag-ZnO-Ag disk sub-cells with anti-reflection layers, which can synchronously improve the visible transmittance and widen absorption bandwidth in the non-atmospheric window by enhancing and merging resonance response of multi-resonators.

Catenary optics: a perspective of applications and challenges.

Catenary optics is an emerging direction of subwavelength optics, which is indispensable in describing the electric fields and dispersion property of coupled metallic subwavelength structures, and designing broadband high-efficiency geometric-phase metasurfaces. It involves catenary optical fields and catenary structures, in which both ordinary and equal-length catenary functions play important roles. In recent years, catenary optics has realized a variety of exotic phenomena and optical applications, including broadband photonic spin-Hall effect, super-resolution lithography, broadband absorbers, and extreme-angle imaging.

Designing high-efficiency extended depth-of-focus metalens via topology-shape optimization.

Longitudinal optical field modulation is of critical importance in a wide range of applications, including optical imaging, spectroscopy, and optical manipulation. However, it remains a considerable challenge to realize a uniformly distributed light field with extended depth-of-focus. Here, a high-efficiency extended depth-of-focus metalens is proposed by adjoint-based topology-shape optimization approach, wherein the theoretical electric field intensity corresponding to a variable focal-length phase is utilized as the figure of merit.