Kong Soon-Cheol, Taflove Allen, Backman Vadim
Department of Electrical Engineering and Computer Science, Northwestern University, Evanston, IL 60208, USA.
Opt Express. 2009 Mar 2;17(5):3722-31. doi: 10.1364/oe.17.003722.
An optically illuminated micron-scale dielectric sphere can generate a photonic nanojet - a nonresonant propagating beam phenomenon of high amplitude, narrow waist, and substantial sensitivity to the presence of nanometer-scale particles and geometric features located within the beam. Via three-dimensional finite-difference time-domain computational electrodynamics modeling of illuminated graded-index microspheres, we have found that the useful length of a photonic nanojet can be increased by an order-of-magnitude to approximately 20 wavelengths. This is effectively a quasi one-dimensional light beam which may be useful for optical detection of natural or artificially introduced nanostructures deeply embedded within biological cells. Of particular interest in this regard is a potential application to visible-light detection of nanometer-scale anomalies within biological cells indicative of early-stage cancer.
一个由光照射的微米级介质球可以产生一个光子纳米射流——一种高振幅、窄束腰且对位于光束内的纳米级粒子和几何特征的存在具有显著敏感性的非共振传播光束现象。通过对受照渐变折射率微球进行三维时域有限差分计算电动力学建模，我们发现光子纳米射流的有效长度可以增加一个数量级，达到约20个波长。这实际上是一种准一维光束，可能有助于对深埋在生物细胞内的天然或人工引入的纳米结构进行光学检测。在这方面，特别令人感兴趣的是其在可见光检测生物细胞内指示早期癌症的纳米级异常方面的潜在应用。
