Optical tweezers and associated manipulation tools in the far field have had a major impact on scientific and engineering research by offering precise manipulation of small objects. More recently, the possibility of performing manipulation with surface plasmons has opened opportunities not feasible with conventional far-field optical methods. The use of surface plasmon techniques enables excitation of hotspots much smaller than the free-space wavelength; with this confinement, the plasmonic field facilitates trapping of various nanostructures and materials with higher precision. The successful manipulation of small particles has fostered numerous and expanding applications. In this paper, we review the principles of and developments in plasmonic tweezers techniques, including both nanostructure-assisted platforms and structureless systems. Construction methods and evaluation criteria of the techniques are presented, aiming to provide a guide for the design and optimization of the systems. The most common novel applications of plasmonic tweezers, namely, sorting and transport, sensing and imaging, and especially those in a biological context, are critically discussed. Finally, we consider the future of the development and new potential applications of this technique and discuss prospects for its impact on science.

The imaging resolution in turbid media is severely degraded by light scattering. Resolution can be improved if the unscattered or weakly scattered light is extracted. Here the state of polarization of the emerging light is used to discriminate photon path length, with the more weakly scattered photons maintaining their original polarization state. It is experimentally demonstrated that over a wide range of scatterer concentrations there exist three distinct imaging regimes. It is also shown that within the intermediate regime one of two distinct imaging techniques is appropriate, depending on the particle size.

Intriguing anisotropic electrical and optoelectrical properties in twodimensional (2D) materials are currently gaining increasing interest both for fundamental research and emerging optoelectronic devices. Identifying promising new 2D materials with low-symmetry structures will be rewarding in the development of polarizationintegrated nanodevices. In this work, the anisotropic electron transport and optoelectrical properties of multilayer 2D ternary Ta 2 NiSe 5 were systematically researched. The polarization-sensitive Ta 2 NiSe 5 photodetector shows a linearly anisotropy ratio of ≈3.24 with 1064 nm illumination. The multilayer Ta 2 NiSe 5 -based field-effective transistors exhibit an excellent field-effective mobility of 161.25 cm 2 •V −1 •s −1 along the a axis (armchair direction) as well as a great current saturation characteristic at room temperature. These results will promote a better understanding of the optoelectrical properties and applications in new categories of the in-plane anisotropic 2D materials.

Phase and polarization singularities are important degrees of freedom for electromagnetic field manipulation. Detecting these singularities is essential for modern optics, but it is still a challenge, especially in integrated optical systems. In this paper, we propose an on-chip plasmonic spin-Hall nanograting structure that simultaneously detects both the polarization and phase singularities of the incident cylindrical vortex vector beam (CVVB). The nanograting is symmetry-breaking with different periods for the upper and lower parts, which enables the unidirectional excitation of the surface plasmon polariton depending on the topological charge of the incident optical vortex beam. Additionally, spin-Hall meta-slits are integrated onto the grating so that the structure has a chiral response for polarization detection. We demonstrate theoretically and experimentally that the designed structure fully discriminates both the topological charges and polarization states of the incident beam simultaneously. The proposed structure has great potential in compact integrated photonic circuits.