[论文解读] Arbitrarily polarized and unidirectional emission from thermal metasurfaces

J. Ryan Nolen, Adam Overvig+2 more|arXiv (Cornell University)|Jan 28, 2023

Metamaterials and Metasurfaces Applications被引用 9

一句话总结

该论文展示了一个单层超表面，通过在几何相控制下局部定制光子连续带态来实现单向、窄带红外热辐射且具任意偏振。

ABSTRACT

Thermal emission from a hot body is ubiquitous, yet its properties remain inherently challenging to control due to its incoherent nature. Recent advances in thermal emission manipulation have been unveiling exciting phenomena and new opportunities for applications. In particular, judiciously patterned nanoscale features over their surface have been shown to channel emission sources into partially coherent beams with tailored directionality and frequency selectivity. Yet, more sophisticated forms of control, such as spin-selective and unidirectional thermal emission have remained elusive. Here, we experimentally demonstrate single-layer metasurfaces emitting unidirectional, narrowband thermal light in the infrared with arbitrary polarization states - an operation enabled by photonic bound states in the continuum locally tailored by a geometric phase controlling the temporal and spatial coherence of emitted light. The demonstrated platform paves the way to a compactification paradigm for metasurface optics, in which thermal emission or photoluminescence can feed arbitrarily patterned beams without the need of external coherent sources.

研究动机与目标

• 激发并使对比传统漫射输出的非相干热辐射可控成为可能。
• 证明超表面图案化可以将热辐射定向到单向、偏振可定制的束。
• 展示一个平台，在没有外部相干源的情况下能够选择性引导热辐射。

提出的方法

• 在超表面上 pattern 纳米尺度特征以通过连续带态来调控发射。
• 使用几何相控制来定制发射光的时域与空间相干性。
• 在单层结构中实验证明具任意偏振的单向、窄带红外发射。
• 表征对连续带态的局部定制如何影响发射方向性与偏振。

实验结果

研究问题

• RQ1 单层超表面是否可实现具窄带的单向热辐射？
• RQ2 在保持方向性的同时，是否可以从热超表面发射任意偏振态？
• RQ3 连续带态和几何相如何共同作用以实现对热辐射相干性的控制？
• RQ4 在没有外部相干源的情况下，紧凑型基于超表面的热发射器有哪些实际应用意义？

主要发现

• 实现了来自热超表面的单向、窄带红外热发射。
• 发射偏振可任意选择，从而实现不同偏振态。
• 对连续带态进行了局部定制，通过几何相机制控制发射。
• 该方法实现了在没有外部相干源的情况下的热束定制。