Optofluidic transport and assembly of nanoparticles using an all-dielectric quasi-BIC metasurface

Abstract

Manipulating fluids by light at the micro/nanoscale has been a long-sought-after goal for lab-on-a-chip applications. Plasmonic heating has been demonstrated to control microfluidic dynamics due to the enhanced and confined light absorption from the intrinsic losses of metals. Dielectrics, the counterpart of metals, has been used to avoid undesired thermal effects due to its negligible light absorption. Here, we report an innovative optofluidic system that leverages a quasi-BIC-driven all-dielectric metasurface to achieve subwavelength scale control of temperature and fluid motion. Our experiments show that suspended particles down to 200 nanometers can be rapidly aggregated to the center of the illuminated metasurface with a velocity of tens of micrometers per second, and up to millimeter-scale particle transport is demonstrated. The strong electromagnetic field enhancement of the quasi-BIC resonance increases the flow velocity up to three times compared with the off-resonant situation by tuning the wavelength within several nanometers range. We also experimentally investigate the dynamics of particle aggregation with respect to laser wavelength and power. A physical model is presented and simulated to elucidate the phenomena and surfactants are added to the nanoparticle colloid to validate the model. Our study demonstrates the application of the recently emerged all-dielectric thermonanophotonics in dealing with functional liquids and opens new frontiers in harnessing non-plasmonic nanophotonics to manipulate microfluidic dynamics. Moreover, the synergistic effects of optofluidics and high-Q all-dielectric nanostructures hold enormous potential in high-sensitivity biosensing applications.

Optical bound states in the continuum in periodic structures: mechanisms, effects, and applications

“…The enhanced optical forces by the confinement of light were reported and applied to trap nanoparticles [108][109][110] . The near-field enhancement of quasi-BICs will also cause a localized heating effect, which was reported to realize optofluidic transport and assembly of nanoparticles [111] [Fig. 9(c)].…”

“…(b) Negative refraction mediated by BICs [106] . (c) Optofluidic transport and assembly of nanoparticles by utilizing strong electromagnetic field enhancement of the quasi-BIC resonance [111] . (d) Saturated reds by quasi-BICs [112] .…”

Synergy between AI and Optical Metasurfaces: A Critical Overview of Recent Advances

“…It is a short cross-section of the state of the art presented for illustrative purposes only, i.e., without systematization, while the real number of applications, patents and research teams is hard even to guess since it increases on a daily basis. As far as the more advanced applications are concerned, some of them include optofluidic devices [100] for microreactors encompassing photocatalysis [101], lab-on-chip technologies [102]; optical tweezers for micro-and nanoparticle trapping and manipulation [103]; optical levers for atomic force microscopy [104]; biomedical imaging [105], e.g., optical coherence tomography [106], terahertz imaging [107]; super-resolution microscopy beyond the Abbe diffraction limit [108] including the use of superlenses and hyperlenses [109]; nonlinear optical devices for frequency conversion [110]; quantum optics [33] for quantum computing [111] and quantum cryptography [112]; stealth coatings [113]; optical cloaking devices (invisibility shields) [114,115], nonreciprocal cloaking (cloak that hides objects from the outside viewpoint but permits looking from the object outward) [116]; camouflage into virtual objects (electromagnetic illusions) [117,118]; and general transformation optics [119] (including its applications in, e.g., astrophysical all-optical simulation and the related models in other fields [120]).…”

Plasmonic Bound States in the Continuum Metasurface–Semiconductor–Metal Architecture Enables Efficient Hot-Electron-Based Photodetector

“…The core appeal of SP-BIC is their ability to precisely control resonance properties by tuning the geometrical parameters. When the symmetric protection is broken by destructive interference between two resonate channels, the perfect BIC with disappeared line width will degrade into the quasi (q)-BIC, causing a strong and wide resonance peak that can be observed in the far-field. , Currently, the research on BIC primarily revolves around the pursuit of high and robust Q factors based on radiative leaking for the application of nanocavity lasing, microfluidic dynamics manipulating, ultrahigh-sensitivity biosensing, , and so on. , However, utilizing relatively low Q factors to achieve strong light–matter interactions, particularly in the field of plasmonic HEB-PDs, has rarely been explored or discussed.…”