A reflective metasurface that can form a non-diffraction beam is proposed in this article. This metasurface is designed based on the artificial admittance modulation surface, and the metallic square patch on the grounded dielectric substrate is utilized to construct the whole surface. The beam can change its propagation direction with the change of frequency and have good non-diffraction characteristics. The metasurface is fabricated, and the measurement results demonstrate good performance of generating non-diffraction beams.

Silicon dielectric metasurfaces based on a square lattice of nanoparticles have been extensively utilized to create transmissive structural colors. Yet it is a huge challenge to obtain stable yellow color with high saturation due to the relatively large absorption of silicon in the short wavelength regime and the applied square lattice. In this study, we propose a new design strategy of independently altering the mutually perpendicular periods of a hydrogenated amorphous silicon nanodisk array-enabled metasurface to meticulously modulate the transmission spectra for the realization of high-saturation and stable cyan, magenta and yellow (CMY) color pixels. By introducing rectangular lattice, the yellow pixel can provide a narrowband transmission spectrum with a highly suppressed dip at 455 nm. The high suppression in transmission contributes to give rise to high-saturation yellow color. The attained narrowband spectrum that enables low spectral cross-talk is attributed to the overlap between magnetic dipole resonance excited by individual nanodisks and lattice resonance arising from the dipole coupling between the nanodisks. Compared with the square lattice, the proposed pixels exhibit fairly stable output color responses for a large period range. Meanwhile, the proposed CMY pixels are capable of both the relaxed angular tolerance and low dependence on the incident polarization states. It is anticipated that the proposed color pixels pave the way for extensive applications in compact color displays.

A metasurface-based switchable optical trapping scheme was demonstrated utilizing twofold vortex-pair beams for stable, flexible, and efficient microparticle manipulation.

As a promising technology, refractive index (RI) sensing has been developed for biosensing and chemosensing applications as well as for multiple industrial applications. Nevertheless, conventional RI sensors are confined by their operating principle or detection devices in terms of high sensitivity or a wide detection range. This study experimentally demonstrates metasurface-based spectrometer-free RI sensing through a spatial weighted variance (SWV)-based analysis of metasurface-generated vortex beams. The proposed liquid-immersed metasurface device creates a focused vortex beam at a single wavelength of 1550 nm, whose focusing effect varies according to the surrounding medium. The images, captured by a position-fixed near-infrared camera, exhibit divergent beam profiles determined by certain RI values. The SWV is used to assess the degree of divergence and is calculated based on the recorded beam images to quantify the variation of the RI. Thus, the proposed RI sensing scheme concurrently achieves high sensitivity (113 598/RIU), wide detection range (1.3164–1.3825), and high resolution (8.8 × 10−6 RIU). The proposed image-based spectrometer-less RI sensing methods overcome the constraints of instruments that are unavoidable in conventional detection techniques. Compared to the existing methods, the proposed strategy is simpler, less costly, more user-friendly, and usable in a broader range of sensing applications.

Transition metal dichalcogenide (TMD) materials have demonstrated promising potential for applications in photodetection due to their tunable bandgaps, high carrier mobility, and strong light absorption capabilities. However, limited by their intrinsic bandgaps, TMDs are unable to efficiently absorb photons with energies below the bandgap, resulting in a significant attenuation of photoresponse in spectral regions beyond the bandgap. This inherently restricts their broadband photodetection performance. By introducing metasurface structures consisting of subwavelength optical elements, localized plasmon resonance effects can be exploited to overcome this absorption limitation, significantly enhancing the light absorption of TMD films. Additionally, the heterogeneous integration process between the metasurface and two-dimensional materials offers low-temperature compatibility advantages, effectively avoiding the limitations imposed by high-temperature doping processes in traditional semiconductor devices. Here, we systematically investigate metasurface-enhanced two-dimensional MoSe₂ photodetectors, demonstrating broadband responsivity extension into the mid-infrared spectrum via precise control of metasurface structural dimensions. The optimized device possesses a wide spectrum response ranging from 808 nm to 10 μm, and the responsivity (R) and specific detection rate (D*) under 4 μm illumination achieve 7.1 mA/W and 1.12 × 10⁸ Jones, respectively. Distinct metasurface configurations exhibit varying impacts on optical absorption characteristics and detection spectral ranges, providing experimental foundations for optimizing high-performance photodetectors. This work establishes a practical pathway for developing broadband optoelectronic devices through nanophotonic structure engineering.