Chemically synthesized metal nanowires are promising building blocks for next-generation photonic integrated circuits, but technological implementation in monolithic integration will be severely hampered by the lack of controllable and precise manipulation approaches, due to the strong adhesion of nanowires to substrates in non-liquid environments. Here, we demonstrate this obstacle can be removed by our proposed earthworm-like peristaltic crawling motion mechanism, based on the synergistic expansion, friction, and contraction in plasmon-driven metal nanowires in non-liquid environments. The evanescently excited surface plasmon greatly enhances the heating effect in metal nanowires, thereby generating surface acoustic waves to drive the nanowires crawling along silica microfibres. Advantages include sub-nanometer positioning accuracy, low actuation power, and self-parallel parking. We further demonstrate on-chip manipulations including transporting, positioning, orientation, and sorting, with on-situ operation, high selectivity, and great versatility. Our work paves the way to realize full co-integration of various functionalized photonic components on single chips.

Nanorobotic motion on solid substrates is greatly hindered by strong nanofriction, and powerful nanomotors‒the core components for nanorobotic motion‒are still lacking. Optical actuation addresses power and motion control issues simultaneously, while conventional technologies with small thrust usually apply to fluid environments. Here, we demonstrate micronewton-thrust nanomotors that enable the autonomous nanorobots working like conventional robots with precise motion control on dry surfaces by a photothermal-shock technique. We build a pulsed laser-based actuation and trapping platform, termed photothermal-shock tweezers, for general motion control of metallic nanomaterials and assembled nanorobots with nanoscale precision. The thrust-to-weight ratios up to 10⁷ enable nanomotors output forces to interact with external micro/nano-objects. Leveraging machine vision and deep learning technologies, we assemble the nanomotors into autonomous nanorobots with complex structures, and demonstrate multi-degree-of-freedom motion and sophisticated functions. Our photothermal shock-actuation concept fundamentally addresses the nanotribology challenges and expands the nanorobotic horizon from fluids to dry solid surfaces.

Subwavelength diameter micro/nanofiber (MNF) provides excellent platform for many applications. In this work, we fabricate subwavelength diameter MNFs with ultra-long waist and analyze the propagation loss origin for such fibers. Transmittance as high as 99.4% is measured for MNF with a waist length of 10 cm and diameter of $1.2\mu \text{m}$ , and the loss is mainly resulted from the modal leakage of the taper. However, when the MNF is getting longer and thinner, the intrinsic surface roughness induced during the fabrication process overrides the modal leakage and plays a major role in the propagation loss. Our study reveals existence of an ultimate transmission limitation for ultra-long MNFs.

Implementing compact, efficient, and reliable passive pulsed lasers at visible wavelengths is attractive. This paper systematically investigated the thickness-dependent optical absorption characteristics of two-dimensional materials, including graphene, transition-metal dichalcogenides, and dye films at the 532 nm wavelength band, and revealed the effects of thickness on different optical absorption parameters. The results suggested that dye films are more suitable for loss-sensitive pulsed lasers and graphene is more suitable for modulation depth-sensitive pulsed lasers, while transition-metal dichalcogenide samples have intermediate performance. It can provide guidance for the rational selection of saturable absorbers in pulsed all-fiber lasers to optimize the optical pulse performance in the visible-wavelength band.

Experimental near‐field analysis of the output beams from the end faces of micro/nano‐waveguide is very necessary, because important information such as spatial intensity distributions, mode orders, and divergence angles can be obtained, and are very important for investigating and designing nanophotonic devices. However, as far as we know, it has not been demonstrated yet. In this work, we experimentally demonstrate a plasmonic‐nanowire near‐field beam analyzer, utilizing a single Au nanowire (AuNW) as the probe to scan the spatial near‐field distributions of emitted beams from micro/nano‐waveguide end‐faces. Our analyzer can resolve the trade‐off between high measurement resolution and light collection efficiency in conventional beam analyzers by a reverse nanofocusing process, achieving a probe resolution of 190 nm (< λ /8) and a simulated collection efficiency of ∼47.4 % at λ = 1596 nm. These attractive advantages allow us to obtain three‐dimensional (3D) scanning in a large range from the plasmonic hotspot region to the far‐field region, characterizing the 3D spatial distribution evolution from a metal nanowire output beam for the first time, with an M ² factor lower than that of the ideal Gaussian beam ( M ² = 1). In addition, the analyzer also demonstrates simultaneous characterization of multimodes in irregular and large‐sized nanoribbons, further verifying its ability to selectively explore complex multimodes that are difficult to be predicted by numerical simulations. Our results suggest that this plasmonic‐nanowire beam analyzer may hold promise for diverse near‐field applications for micro/nano‐waveguides such as nanolasers and biosensing, and offer a new method for understanding nanophotonic structures.