Nanoparticle Trapping in a Quasi-BIC System
Nanoparticle Trapping in a Quasi-BIC System
复制标题
DOI：
10.1021/acsphotonics.0c01941
复制
发表时间：
2021-06
期刊：
影响因子：
7
通讯作者：
Sen Yang;Chuchuan Hong;Yuxi Jiang;Justus C. Ndukaife
中科院分区：
文献类型：
--
作者：
Sen Yang;Chuchuan Hong;Yuxi Jiang;Justus C. Ndukaife
采用金属纳米天线的等离子体纳米镊子为捕获纳米级颗粒提供了强大的工具，但由光吸收引起的强烈加热效应限制了广泛的应用。在这里，我们提出了一个alldielectric nanotweezer利用准束缚态的连续（准BIC），使低激光功率和可忽略不计的加热效应的纳米级物体的陷阱。准BIC系统提供比等离子体系统高一个数量级的非常高的电磁场强度增强以及与光子晶体腔相当的高品质因数共振。此外，准BIC超颖表面镊子阵列提供具有高场限制和增强的多个光学热点，从而产生用于纳米级物体的高通量捕获的多个捕获位点。通过有目的地截断在准BIC系统中的组成椭圆形纳米天线的尖端，以利用不对称的场分布，我们证明了光梯度力可以进一步增强的因素相比，完整的椭圆形纳米天线，这在亚波长粒子捕获应用中具有吸引力的潜力的1.32。此外，我们发现，捕获的粒子可以提高谐振腔的共振模式，而不是抑制它在一个破碎的系统，这反过来又增强了捕获过程。我们的研究为将准BIC系统应用于低功耗粒子捕获和传感应用铺平了道路，并提供了一种新的机制来利用自诱导反作用。
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 alldielectric 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 quasiBIC systems to low-power particle trapping and sensing applications and provides a new mechanism to harness the self-induced back-action.