Real-time monitoring and visualization of the multi-dimensional motion of an anisotropic nanoparticle

Abstract

As interest in anisotropic particles has increased in various research fields, methods of tracking such particles have become increasingly desirable. Here, we present a new and intuitive method to monitor the Brownian motion of a nanowire, which can construct and visualize multi-dimensional motion of a nanowire confined in an optical trap, using a dual particle tracking system. We measured the isolated angular fluctuations and translational motion of the nanowire in the optical trap, and determined its physical properties, such as stiffness and torque constants, depending on laser power and polarization direction. This has wide implications in nanoscience and nanotechnology with levitated anisotropic nanoparticles.

Scannable Dual-Focus Metalens with Hybrid Phase

“…In particular, metalenses making two focal spots in the longitudinal or transverse direction, called bifocal or dual-focus metalens, are promising building blocks for various applications, including optical communications, − multi-imaging systems, , tomography technique, − data storage, , and optical tweezers. − In these applications, relative movement between the light beam and specimen is often required. For instance, one-dimensional nanoparticles, such as nanowires, which act as probes for high-resolution photonic force microscopy, should be stably trapped by dual focusing and displaced to measure a single-molecule force or scan a biological specimen. − Fundamentally, this movement can be achieved by employing a specimen translation stage with a stationary light beam (stage scanning) or a scanned light beam with a stationary stage (beam scanning). Stage scanning is built in the early stages of new idea development, owing to its simplicity.…”