Plasmonic nanotweezers employing metallic nanoantennas provide a powerful tool for trapping nanoscale particles, but the strong heating effect resulting from light absorption limits widespread applications. Here, we propose an all-dielectric nanotweezer harnessing quasi-bound states in the continuum (quasi-BICs) to enable the trapping of nanoscale objects with low laser power and a negligible heating effect. The quasi-BIC system provides very high electromagnetic field intensity enhancement that is an order of magnitude higher than plasmonic systems as well as high-quality-factor resonances comparable to photonic crystal cavities. Furthermore, the quasi-BIC metasurface tweezer array provides multiple optical hotspots with high field confinement and enhancement, thereby generating multiple trapping sites for the high-throughput trapping of nanometer-scale objects. By purposefully truncating the tips of the constituent elliptical nanoantennas in the quasi-BIC system to leverage the asymmetric field distribution, we demonstrate that the optical gradient forces can be further enhanced by a factor of 1.32 in comparison to the intact elliptical nanoantenna, which has attractive potential in subwavelength particle trapping applications. In addition, we show that trapped particles can improve the resonance mode of the cavity rather than suppress it in a symmetry-broken system, which in turn enhances the trapping process. Our study paves the way for applying quasi-BIC systems to low-power particle trapping and sensing applications and provides a new mechanism to harness the self-induced back-action.

中文翻译：

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准 BIC 系统中的纳米粒子捕获

采用金属纳米天线的等离子体纳米镊子为捕获纳米级粒子提供了强大的工具，但光吸收产生的强烈加热效应限制了其广泛应用。在这里，我们提出了一种全介电纳米镊子，它利用连续介质中的准束缚态（准 BIC）来捕获具有低激光功率和可忽略不计的加热效应的纳米级物体。准 BIC 系统提供非常高的电磁场强度增强，比等离子体系统高一个数量级，以及与光子晶体腔相当的高质量因子共振。此外，准 BIC 超表面镊子阵列提供了多个具有高场限制和增强的光学热点，从而为纳米尺度物体的高通量捕获产生多个捕获位点。通过有目的地截断准 BIC 系统中组成椭圆纳米天线的尖端以利用不对称场分布，我们证明与完整的椭圆纳米天线相比，光学梯度力可以进一步增强 1.32 倍，具有吸引力亚波长粒子俘获应用的潜力。此外，我们表明被捕获的粒子可以改善腔的共振模式，而不是在对称破坏系统中抑制它，这反过来又增强了捕获过程。我们的研究为将准 BIC 系统应用于低功率粒子捕获和传感应用铺平了道路，并提供了一种利用自诱导反作用的新机制。