We establish the angle-resolved thermal emission spectroscopy (ARTES) as a new platform to characterize the intrinsic eigenmode properties of non-Hermitian systems. This method can directly map the dispersion of meta-crystals within the light cone with a high angular resolution. To illustrate its usefulness, we demonstrate the existence of bound states in the continuum (BICs) and non-Hermitian Fermi arcs in a planar corrugated meta-crystal by measuring its angle-resolved thermal emission spectra. We show that change in the thickness of the meta-crystal can induce a band inversion between a BIC and a radiative state, and a pair of exceptional points emerge when the band inversion occurs. With this approach, the band mapping of non-Hermitian photonic systems can become a relatively striaghtforward task.

中文翻译：

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非Hermitian偏晶的角度分辨热发射光谱表征

我们建立了角度分辨热发射光谱（ARTES）作为表征非Hermitian系统固有本征模特性的新平台。该方法可以以高角度分辨率直接映射亚锥内的亚晶体的色散。为了说明其有用性，我们通过测量其角度分辨的热发射光谱，证明了平面波纹形超晶体中连续体（BIC）和非赫米特费米弧的束缚态的存在。我们表明，准晶厚度的变化会引起BIC和辐射态之间的能带反转，并且当能带反转发生时会出现一对例外点。通过这种方法，非赫米特光子系统的能带映射可以成为一项相对超前的任务。