葡萄的期望：微波米氏谐振器中电场的直接热成像
Grape expectations: direct thermographic imaging of electric fields in microwave Mie resonators
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中文总结 AI 辅助
该研究利用葡萄作为高折射率纳米光子谐振器的类似物，通过偏振控制自由空间激发和红外热成像直接测量微波米氏谐振器的电场，明确了葡萄二聚体中微波诱导热点的形成条件，为相关场的测量与控制提供了新方法。
中文摘要 AI 辅助
内部电磁场决定了介质纳米谐振器的行为，但由于亚波长尺度超出了常规光学测量的范围，且任何能进行局域传感的探针都会干扰其试图测量的场，因此直接测量这些场极其困难。我们利用水在微波频率下的高折射率规避了这一限制，这使得厘米级的水性球体——葡萄——可作为高折射率纳米光子谐振器的直接可测量、尺度不变的类似物。使用偏振控制的自由空间激发和红外热成像，我们证明葡萄内部的加热模式与基磁偶极和电偶极米氏谐振的模拟电场分布密切吻合，但与磁场分布不吻合。将该方法扩展到葡萄二聚体，我们证明与微波诱导火花相关的远小于波长的物体间热点仅在轴向偏振下形成，这既为其起源提供了线索，也为其控制提供了手段。
英文摘要
Internal electromagnetic fields determine the behaviour of dielectric nano-resonators, yet they remain exceptionally difficult to measure directly because subwavelength scales place them beyond conventional optical measurement, and any probe capable of local sensing perturbs the field it seeks to measure. We circumvent this limitation using water's high refractive index at microwave frequencies, which lets centimetre-scale aqueous spheres---grapes---serve as directly measurable, scale-invariant analogs of high-index nanophotonic resonators. Using polarization-controlled free-space excitation and infrared thermography, we show that internal heating patterns in grapes closely track simulated electric-, but not magnetic-, field distributions for both the fundamental magnetic- and electric-dipole Mie resonances. Extending this approach to grape dimers, we demonstrate that the massively sub-wavelength inter-object hotspot associated with microwave-induced sparking forms only under axial polarization, thus providing both a clue to its origin and a means for its control.
