Optical tweezers (OTs) can transfer light momentum to particles, achieving the precise manipulation of particles through optical forces. Due to the properties of non-contact and precise control, OTs have provided a gateway for exploring the mysteries behind nonlinear optics, soft-condensed-matter physics, molecular biology, and analytical chemistry. In recent years, OTs have been combined with microfluidic chips to overcome their limitations in, for instance, speed and efficiency, creating a technology known as “optofluidic tweezers.” This paper describes static OTs briefly first. Next, we overview recent developments in optofluidic tweezers, summarizing advancements in capture, manipulation, sorting, and measurement based on different technologies. The focus is on various kinds of optofluidic tweezers, such as holographic optical tweezers, photonic-crystal optical tweezers, and waveguide optical tweezers. Moreover, there is a continuing trend of combining optofluidic tweezers with other techniques to achieve greater functionality, such as antigen–antibody interactions and Raman tweezers. We conclude by summarizing the main challenges and future directions in this research field.

Virtual synchronous generators (VSGs) are susceptible to transient instability, especially under large disturbances without equilibrium points (EPs). This paper proposes an additional frequency control to restore EPs and ensure transient stability. In this control, the damping effect is enhanced to improve the transient behavior, and the additional potential energy is introduced to restore EPs after detecting the transient instability characteristics of VSGs. Compared with previous stabilizing methods, the proposed method can address transient stability issues both with and without EPs, and it does not rely on any grid information. Simulations and experiments validate the effectiveness of this method.

Optical tweezers based on plasmonics experience a tremendous development on manipulating nanoparticles but are unable to avoid the problem of Joule heating. In this Letter, we report a silicon nanotrimer to optically trap and manipulate nanoparticles with negligible local heating. The optical forces and trapping potential of the nanotrimer are investigated using the finite-difference time-domain method. The results indicate that the trapping position can be shifted by tuning the polarization of the incident light. Furthermore, the silicon nanotrimer enables simultaneous trapping of multiple nanoparticles using circularly polarized illumination. Our work provides a promising building block for an integrated all-dielectric platform to realize optically driven nanomanipulation, which offers new possibilities for on-chip optical applications.

Harnessing exotic optical forces promises a plethora of biophysical applications and novel light-matter interactions. The exotic optical pulling force (OPF) and optical lateral force (OLF) have been studied separately, yet synthesizing both candidates simultaneously remains an unsolved challenge and could offer a more powerful manoeuvre of particles. Here, we report a coordinated scheme to harness these two forces together and present a dynamically controlled two-dimensional (2D) microvehicle. The strategy is to leverage unexplored helicity-dependent features of both forces, while the particle size and incident angle of light can also reverse optical forces. The underlying physics of the pulling-lateral force is beyond the dipole approximation, and can be the combined effect from the linear momentum transfer, spin-orbit interactions, etc. Notably, the ratio of both forces can be dynamically and arbitrarily controlled by the ellipticity of incident light solely. The configured 2D microvehicle provides a nontrivial recipe other than using metastructures which require exquisite designs and subtle fabrication processes.