Microscopic metavehicles powered and steered by embedded optical metasurfaces

Abstract

Nanostructured dielectric metasurfaces offer unprecedented opportunities to manipulate light by imprinting an arbitrary phase-gradient on an impinging wavefront. 1 This has resulted in the realization of a range of flat analogs to classical optical components like lenses, waveplates and axicons. 2-6 However, the change in linear and angular optical momentum 7 associated with phase manipulation also results in previously unexploited forces acting on the metasurface itself. Here, we show that these optomechanical effects can be utilized to construct optical metavehicles -microscopic particles that can travel long distances under low-power plane-wave illumination while being steered through the polarization of the incident light. We demonstrate movement in complex patterns, self-correcting motion, and an application as transport vehicles for microscopic cargo, including unicellular organisms. The abundance of possible optical metasurfaces attests to the prospect of developing a wide variety of metavehicles with specialized functional behavior.One of the most distinguishing features of optical metasurfaces is their ability to simultaneously manipulate a wave's propagation direction and polarization despite being sub-wavelength in thickness. This results in an exchange of linear and angular momentum between light and matter and, by virtue of Newton's third law, optical forces and torques acting on the metasurface. Two main challenges need to be overcome in order to exploit this phenomenon for the practical realization of microparticles capable of movement and steering in a plane-wave light field (Figure 1). First, the microparticle should contain a metasurface that efficiently bends light towards a

The Dawn of Metadevices: From Contemporary Designs to Exotic Applications

“…An added advantage is their ability to self-correct their motion while acting as locomotives for microscopic cargo and unicellular organisms. They have been shown to transport other microscopic objects by lateral pushing [168].…”

Optically Triggered Nanoscale Plasmonic Dynamite

“…Actuation and propulsion by light is a convenient way to manipulate nano-objects/micro-objects with remote controllability, which are mostly based on optical forces and photothermal-induced forces, − but again their force output is small (∼pN) and speed is slow, which strongly restrict their performances to liquid environment or semiliquid interface . Although laser-induced metal jetting and ablation can be used for forward transfer of nanoparticles in an efficient and controllable manner in dried state, in-plane manipulation and generality of this technique are still limited .…”

Negative radiation pressure in metamaterials explained by light-driven atomic mass density rarefication waves

“…Homogenization of material parameters and fields may also be applied 12 , 13 , 18 – 20 . On the experimental side, the optical forces on metasurfaces have been very recently applied to drive microvehicles 21 , but their use has not yet reached phenomena of light propagating inside NIM structures. The non-averaged exact position- and time-dependent optical force and momentum densities of light in NIMs can be obtained by solving simultaneously Maxwell’s equations for the field and the Newtonian dynamics of the solid, neutral material.…”