Wang Jinzhi, Wang Chao, Han Zhe, Tian Huiping
Opt Express. 2022 Mar 28;30(7):11192-11202. doi: 10.1364/OE.449193.
In this work, we propose a slotted photonic crystal nanobeam cavity (PCNC) to trap and sort the 120 nm and 30 nm nanoparticles. The simulation shows that the maximum optical trapping force of the 120 nm particle is 38.7 pN/mW, and that of the 30 nm particle is 10.8 pN/mW. It is calculated that the trapping threshold power of the 120 nm particle is 35.3 µW, and that of the 30 nm particle is 41.6 µW. Because the width of the slot is 100 nm, when the input power is between 35.3 µW and 41.6 µW, only the 120 nm particle can be trapped in the upper cladding of the slotted-PCNC. When the input power is greater than 41.6 µW, the 120 nm particle is still trapped in the upper cladding of the slotted-PCNC, while the 30 nm particle is trapped inside the slot of the slotted-PCNC. By properly controlling the input power and the direction of flow in the microfluidic channel, the sorting of particles can be achieved. In addition, trapping of the particles causes different redshifts of peak wavelengths. Thus, the proposed slotted-PCNC can detect particle trapping and sorting by monitoring the resonant wavelength shifts. What is the most important, compared with previous reported single particle trapping work, is that the proposed work can realize both trapping and sorting. Therefore, provided with the ultra-compact footprint and excellent performance, the proposed slotted-PCNC shows great potential for a multifunctional lab-on-a-chip system.
在这项工作中，我们提出了一种开槽光子晶体纳米光束腔（PCNC）来捕获和分选120纳米和30纳米的纳米颗粒。模拟结果表明，120纳米颗粒的最大光捕获力为38.7皮牛/毫瓦，30纳米颗粒的最大光捕获力为10.8皮牛/毫瓦。经计算，120纳米颗粒的捕获阈值功率为35.3微瓦，30纳米颗粒的捕获阈值功率为41.6微瓦。由于狭缝宽度为100纳米，当输入功率在35.3微瓦至41.6微瓦之间时，只有120纳米的颗粒能够被捕获在开槽PCNC的上包层中。当输入功率大于41.6微瓦时，120纳米的颗粒仍被捕获在开槽PCNC的上包层中，而30纳米的颗粒则被捕获在开槽PCNC的狭缝内。通过适当地控制输入功率和微流控通道中的流动方向，可以实现颗粒的分选。此外，颗粒的捕获会导致峰值波长出现不同程度的红移。因此，可以通过监测共振波长的偏移来检测所提出的开槽PCNC中颗粒的捕获和分选情况。最重要的是，与先前报道的单颗粒捕获工作相比，本文所提出的工作能够同时实现捕获和分选。因此，所提出的开槽PCNC具有超紧凑的尺寸和优异的性能，在多功能芯片实验室系统中显示出巨大的潜力。
