Simultaneous Control of Spectral And Directional Emissivity with Gradient Epsilon‐Near‐Zero InAs Photonic Structures
Simultaneous Control of Spectral And Directional Emissivity with Gradient Epsilon‐Near‐Zero InAs Photonic Structures
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DOI：
10.1002/adma.202302956
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发表时间：
2022-12
影响因子：
29.4
通讯作者：
J. Hwang;Jin Xu;A. Raman
中科院分区：
文献类型：
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作者：
J. Hwang;Jin Xu;A. Raman
控制发射热辐射的光谱带宽和方向性是当代光子学的基本挑战。最近的研究表明，在其ε近零（ENZ）响应频率范围内具有空间梯度的材料可以支持其发射率的广谱方向性，从而实现特定入射角的高总辐射率。然而，由于在长波红外波长上具有声子极化子共振的材料的可用性，这种能力在光谱和方向上受到限制。这里，使用掺杂的 III-V 族半导体设计并通过实验证明了一种方法，该方法可以同时调整红外发射率的光谱峰值、带宽和方向性。基于 InAs 的梯度 ENZ 光子结构表现出宽带定向发射，其光谱带宽和方向范围随其掺杂浓度分布和厚度的变化而变化，并进行外延生长和表征。由于其易于制造的几何形状，人们相信这种方法提供了一个多功能的光子平台，可以动态控制宽带光谱和定向发射率，适用于传热和红外传感领域的一系列新兴应用。
Controlling both the spectral bandwidth and directionality of emitted thermal radiation is a fundamental challenge in contemporary photonics. Recent work has shown that materials with a spatial gradient in the frequency range of their epsilon‐near‐zero (ENZ) response can support broad spectrum directionality in their emissivity, enabling high total radiance to specific angles of incidence. However, this capability is limited spectrally and directionally by the availability of materials with phonon‐polariton resonances over long‐wave infrared wavelengths. Here, an approach is designed and experimentally demonstrated using doped III–V semiconductors that can simultaneously tailor spectral peak, bandwidth, and directionality of infrared emissivity. InAs‐based gradient ENZ photonic structures that exhibit broadband directional emission with varying spectral bandwidths and directional ranges as a function of their doping concentration profile and thickness are epitaxially grown and characterized. Due to its easy‐to‐fabricate geometry, it is believed that this approach provides a versatile photonic platform to dynamically control broadband spectral and directional emissivity for a range of emerging applications in heat transfer and infrared sensing.