To efficiently integrate cutting-edge terahertz technology into compact devices, the highly confined terahertz plasmons are attracting intensive attention. Compared to plasmons at visible frequencies in metals, terahertz plasmons, typically in lightly doped semiconductors or graphene, are sensitive to carrier density (n) and thus have an easy tunability, which leads to unstable or imprecise terahertz spectra. By deriving a simplified but universal form of plasmon frequencies, here, we reveal a unified mechanism for generating unusual n-independent plasmons (DIPs) in all topological states with different dimensions. Remarkably, we predict that terahertz DIPs can be excited in a two-dimensional nodal line and one-dimensional nodal point systems, confirmed by the first-principle calculations on almost all existing topological semimetals with diverse lattice symmetries. Besides n-independence, the feature of Fermi velocity and degeneracy factor dependencies in DIPs can be applied to design topological superlattice and multiwalled carbon nanotube metamaterials for broadband terahertz spectroscopy and quantized terahertz plasmons, respectively. Surprisingly, high spatial confinement and quality factor, also insensitive to n, can be simultaneously achieved in these terahertz DIPs. Our findings pave the way for developing topological plasmonic devices for stable terahertz applications.

为了将尖端的太赫兹技术有效地集成到紧凑型设备中，高度受限的太赫兹等离子体引起了广泛关注。与金属中可见频率的等离子体激元相比，通常在轻掺杂半导体或石墨烯中的太赫兹等离子体激元对载流子密度 ( n )敏感，因此具有易于调节的特性，这会导致太赫兹光谱不稳定或不精确。通过推导出一种简化但通用的等离子体频率形式，我们揭示了一种生成不寻常n的统一机制- 具有不同维度的所有拓扑状态中的独立等离子体（DIP）。值得注意的是，我们预测太赫兹 DIP 可以在二维节点线和一维节点系统中被激发，这通过对几乎所有现有具有不同晶格对称性的拓扑半金属的第一性原理计算得到证实。除了n独立性之外，DIP 中费米速度和简并因子相关性的特征还可用于设计拓扑超晶格和多壁碳纳米管超材料，分别用于宽带太赫兹光谱和量子化太赫兹等离子体。令人惊讶的是，高空间限制和质量因子，也对n不敏感, 可以在这些太赫兹 DIP 中同时实现。我们的发现为开发用于稳定太赫兹应用的拓扑等离子体设备铺平了道路。