We experimentally demonstrate the trapped rainbow in tapered left-handed heterostructures (LHHs) at visible frequencies. The employed left-handed metamaterials (LHMs) are isotropic with the size of hundreds of square millimeter. Specifically, the LHMs sample at visible frequencies has a broad spectral range and low loss, making it an intrinsic optical response for the LHHs. It is found that the frequency components of the wave packet separate at positions with different guide thicknesses only if the inclination of tapered LHHs is greater than zero and smaller than the critical value.

Dielectric metamaterials based on ceramics have attracted considerable interest in the past few years owing to their low dielectric loss, simple structure, excellent multifield tunability, and good environmental adaptability. They are considered to be promising alternative to metal‐based metamaterials and can lead to a new strategy for the development of passive devices. In this review, the recent progress of ceramic‐based dielectric metamaterials in electromagnetic applications, energy applications, non‐Hermitian systems, and natural materials with near‐zero or negative refraction are summarized. The design principle and mechanism, as well as manufacturing technologies, are also introduced, and the current development trend of ceramic‐based dielectric metamaterials are proposed.

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This article reports a new research method for oxygen vacancy regulation in microwave ceramics and its high frequency response mechanism.