High-Resolution Large-Ensemble Nanoparticle Trapping with Multifunctional Thermoplasmonic Nanohole Metasurface

Abstract

The intrinsic loss in a plasmonic metasurface is usually considered to be detrimental for device applications. Using plasmonic loss to our advantage, we introduce a thermoplasmonic metasurface that enables high-throughput large-ensemble nanoparticle assembly in a lab-on-a-chip platform. In our work, an array of subwavelength nanoholes in a metal film is used as a plasmonic metasurface that supports the excitation of localized surface plasmon and Bloch surface plasmon polariton waves upon optical illumination and provides a platform for molding both optical and thermal landscapes to achieve a tunable many-particle assembling process. The demonstrated many-particle trapping occurs against gravity in an inverted configuration where the light beam first passes through the nanoparticle suspension before illuminating the thermoplasmonic metasurface, a feat previously thought to be impossible. We also report an extraordinarily enhanced electrothermoplasmonic flow in the region of the thermoplasmonic nanohole metasurface, with comparatively larger transport velocities in comparison to the unpatterned region. This thermoplasmonic metasurface could enable possibilities for myriad applications in molecular analysis, quantum photonics, and self-assembly and creates a versatile platform for exploring nonequilibrium physics.

Novel Plasmonic Nanocavities for Optical Trapping‐Assisted Biosensing Applications

“…To turn this drawback into an advantage, new low‐power optical tweezing techniques that capitalize on the photo‐induced heating of plasmonic nanostructures have been devised. [ 110,111 ] Recently, Ndukaife et al have introduced a hybrid electro‐thermo‐plasmonic nanotweezer that exploits the synergistic effects of an externally applied electric field and plasmonic field enhancement of gold nanoantenna, leading to long range trapping of nanoparticles. [ 87,112 ] Most recently, another novel opto‐thermo‐electric trapping technique that exploits plasmonic heating has been developed by Lin et al [ 88 ] By optically heating a thermoplasmonic substrate, a light‐directed thermoelectric field can be generated due to spatial separation of dissolved ions within the heating laser spot, which allows manipulation of nanoparticles of a wide range of materials, sizes and shapes with single‐particle resolution.…”

Flow with nanoparticle clustering controlled by optical forces in quartz glass nanoslits

“…On the contrary, dielectric particles such as polystyrene or biomaterials have small polarizability and are still difficult to be stably trapped. Given such a situation, some non-standard optical trapping techniques, such as plasmonic optical tweezers (Shoji and Tsuboi 2014;Ndukaife et al 2018;Pin et al 2018) or thermophoretic manipulation induced by photothermal effects (Duhr and Braun 2006;Jiang et al 2009;Maeda et al 2012;Lin et al 2018;, have been proposed. These non-standard optical trapping techniques can be combined with the present flow control concept in nanofluidic device to achieve more stable performance.…”

Nanomanipulation with Designer Thermoplasmonic Metasurface

“…In this section, we discuss thermoplasmonic nanotweezer based on nanohole metasurface [50], which enables high-throughput large-ensemble nanoparticle assembly in a lab-on-a-chip platform. As mentioned in previous sections, optical metasurfaces achieve control over the properties of light.…”

“…Electric field distribution of one of the single nanoholes by numerical simulation. Adapted with permission from Ref [50]…”