Photonic nanojets with mesoscale high-index dielectric particles
Photonic nanojets with mesoscale high-index dielectric particles
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DOI：
10.1063/1.5086175
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发表时间：
2019-02-28
影响因子：
3.2
通讯作者：
Beruete, M.
中科院分区：
文献类型：
--
作者：
Pacheco-Pena, V.;Beruete, M.
在这项工作中，我们演示了高折射率介电粒子在空气中产生极高分辨率(类似于0.06lambda(0))的光子纳米喷注的能力。分析了二维(圆柱形)和三维(球形)粒子，并利用固体浸没透镜的魏尔斯特拉斯公式截断了它们的轮廓，在平面波光照下在输出表面产生了光子纳米射流。它们的聚焦能力是通过空间分辨率来评估的，对于截断的圆柱和球体，它们的亚波长值分别类似于0.14和0.06 nm(0)。利用扫描探针显微镜结构评估了截断球增强放置在光子纳米射流附近的两个小金属球散射体产生的后向散射的能力。通过在产生光子纳米喷流的横向平面上移动金属球体，分析了该技术的成像能力。本文的结果极大地提高了具有小折射率对比度的介电粒子产生的光子纳米射流的典型分辨率。此外，高指数材料允许使用中尺度粒子，从而导致更紧凑的设置。这些结果可能会在显微镜、成像和传感设备等需要低于衍射极限的亚波长分辨率的领域中得到应用。
In this work, we demonstrate the ability of high-index dielectric particles immersed in air to generate photonic nanojets with extreme resolution (similar to 0.06 lambda(0)). Both 2D (cylindrical) and 3D (spherical) particles are analyzed, and their profile is truncated using the Weierstrass formulation for solid immersion lenses to produce a photonic nanojet at the output surface under plane wave illumination. Their focusing capability is evaluated in terms of the spatial resolution achieving subwavelength values of similar to 0.14 lambda(0) and similar to 0.06 lambda(0) for a truncated cylinder and sphere, respectively. The capability of the truncated sphere to enhance the backscattering produced by two small metallic spherical scatterers placed near the photonic nanojet is evaluated by using a scanning-probe microscopy configuration. The imaging capabilities of this technique are also analyzed by moving the metallic spheres in the transversal plane where the photonic nanojet is produced. The results presented here improve greatly the typical resolution of photonic nanojets generated with dielectric particles with a small index contrast. In addition, the high-index material allows using mesoscale particles, leading to a more compact setup. These results may find applications in areas such as microscopy, imaging, and sensing devices where a subwavelength resolution below the diffraction limit is needed.