Plasmonic sensing technology has attracted considerable attention for high sensitivity due to the ability to effectively localize and manipulate light. In this study, we demonstrate a refractive index (RI) sensing scheme based on open-loop twisted meta-molecule arrays using the versatile nano-kirigami principle. RI sensing has the features of a small footprint, flexible control, and simple preparation. By engineering the morphology of meta-molecules or the RI of the ambient medium, the chiral surface lattice resonances can be significantly enhanced, and the wavelength, intensity, and sign of circular dichroism (CD) can be flexibly tailored. Utilizing the relation between the wavelength of the CD peak and the RI of the superstrate, the RI sensor achieves a sensitivity of 1133 nm/RIU. Additionally, we analyze these chiroptical responses by performing electromagnetic multipolar decomposition and electric field distributions. Our study may serve as an ideal platform for applications of RI measurement and provide new insights into the manipulation of chiral light–matter interactions.

Micro-optical electromechanical systems (MOEMS) combine the merits of micro-electromechanical systems (MEMS) and micro-optics to enable unique optical functions for a wide range of advanced applications. Using simple external electromechanical control methods, such as electrostatic, magnetic or thermal effects, Si-based MOEMS can achieve precise dynamic optical modulation. In this paper, we will briefly review the technologies and applications of Si-based MOEMS. Their basic working principles, advantages, general materials and micromachining fabrication technologies are introduced concisely, followed by research progress of advanced Si-based MOEMS devices, including micromirrors/micromirror arrays, micro-spectrometers, and optical/photonic switches. Owing to the unique advantages of Si-based MOEMS in spatial light modulation and high-speed signal processing, they have several promising applications in optical communications, digital light processing, and optical sensing. Finally, future research and development prospects of Si-based MOEMS are discussed.Micro-optical electromechanical systems (MOEMS) combine the merits of micro-electromechanical systems (MEMS) and micro-optics to enable unique optical functions for a wide range of advanced applications. Using simple external electromechanical control methods, such as electrostatic, magnetic or thermal effects, Si-based MOEMS can achieve precise dynamic optical modulation. In this paper, we will briefly review the technologies and applications of Si-based MOEMS. Their basic working principles, advantages, general materials and micromachining fabrication technologies are introduced concisely, followed by research progress of advanced Si-based MOEMS devices, including micromirrors/micromirror arrays, micro-spectrometers, and optical/photonic switches. Owing to the unique advantages of Si-based MOEMS in spatial light modulation and high-speed signal processing, they have several promising applications in optical communications, digital light processing, and optical sensing. Finally, future research and development prospects of Si-based MOEMS are discussed.

Plasmonic structural colors have plenty of advantages over traditional colors based on colorants. The pulsed laser provides an important method generating plasmonic structural colors with high efficiency and low cost. Here, we present plasmonic color printing Al nanodisc structures through curvature-driven shape transition. We systematically study the mechanism of morphologic evolution of the Al nanodisc below the thermal melting threshold. A multi-pulse-induced accumulated photothermal effect and subsequent curvature-driven surface atom diffusion model are adopted to explain the controllable shape transition. The shape transition and corresponding plasmonic resonances of the nanodisc can be independently and precisely modulated by controlled irradiations. This method opens new ways towards high-fidelity color prints in a highly efficient and facile laser writing fashion.

Nano-kirigami enables direct and versatile shape transformations from two-dimensional predesigns to three-dimensional (3D) architectures in microscale/nanoscale. Here a new and extensible strategy for cascaded multilayer nano-kirigami is demonstrated in a gold/silicon nitride (Au/SiN) bilayer nanofilm for 3D nanofabrication and visible light manipulation. By employing a focused ion-beam-based Boolean irradiation, rich 3D shape transformation and nested multilayer nanostructures are precisely manufactured, which are well reproduced by developing a modified mechanical model. Based on the multilayer and deformable features of the nano-kirigami structures, potentials in manipulating the phase and intensity of visible light are explored. The developed new nano-kirigami strategies, as well as the novel exotic 3D nanostructures, could be helpful to build a novel platform for 3D nanofabrication and find potential applications in microelectromechanical/nanoelectromechanical systems, holographic display, plasmonics, nanophotonics, biophotonics, etc.

Tunable/reconfigurable metasurfaces that can actively control electromagnetic waves upon external stimuli are of great importance for practical applications of metasurfaces. Here, we demonstrate a reconfigurable nano-kirigami metasurface driven by pneumatic pressure operating in the near-infrared wavelength region. The metasurfaces consist of combined Archimedean spirals and are fabricated in a free-standing gold/silicon nitride nanofilm by employing focused ion beam (FIB) lithography. The deformable spirals are instantly transformed from two dimensional (2D) to three-dimensional (3D) by the FIB-based nano-kirigami process. The 2D–to–3D transformation induces a dramatic irreversible change of the plasmonic quadruple modes and results in significant modulation in reflection by 137%. The suspended porous nano-kirigami metasurface is further integrated with an optofluidics device, with which the optical resonance is reversibly modulated by the pneumatic pressure. This work provides a strategy for tunable/reconfigurable metasurfaces, which are useful to build a promising lab-on-a-chip platform for microfluidics, biological diagnostics, chemical sensing, and pressure monitoring.

In this paper, we derive the analytical expression for the multipole expansion coefficients of scattering and interior fields of a graphene-coated dielectric particle under the illumination of an arbitrary optical beam. By using this arbitrary beam theory, we systematically investigate the optical forces exerted on the graphene-coated particle by a focused Gaussian beam. Via tuning the chemical potential of the graphene, the optical force spectra could be modulated accordingly at resonant excitation. The hybridized whispering gallery mode of the electromagnetic field inside the graphene-coated polystyrene particle is more intensively localized than the pure polystyreneparticle, which leads to a weakened morphology-dependent resonance in the optical forces. These investigations could open new perspectives for dynamic engineering of optical manipulations in optical tweezers applications.61475186, and 11434017).

Gold nanorods (GNRs) have potential applications ranging from biomedical sciences and emerging nanophotonics. In this paper, we will review some of our recent studies on both microscopic and macroscopic manipulation of GNRs. Unique properties of GNR nanoparticles, such as efficient surface plasmon amplifications effects, are introduced. The stable trapping, transferring, positioning and patterning of GNRs with nonintrusive optical tweezers will be shown. Vector beams are further employed to improve the trapping performance. On the other hand, alignment of GNRs and their hybrid nanostructures will be described by using a film stretch method, which induces the anisotropic and enhanced absorptive nonlinearities from aligned GNRs. Realization and engineering of polarized emission from aligned hybrid GNRs will be further demonstrated, with relative excitation–emission efficiency significantly enhanced. Our works presented in this review show that optical tweezers possess great potential in microscopic manipulation of metal nanoparticles and macroscopic alignment of anisotropic nanoparticles could help the macroscopic samples to flexibly represent the plasmonic properties of single nanoparticles for fast, cheap, and high-yield applications.