Terahertz topological plasmon polaritons for robust temperature sensing

TL;DR

This paper proposes a novel temperature sensing method using topological plasmon polaritons in a one-dimensional InSb microsphere chain, demonstrating high sensitivity and robustness due to topological protection.

Contribution

It introduces the first theoretical application of topological plasmon polaritons for temperature sensing, leveraging their robustness and tunability in the terahertz range.

Findings

Temperature sensitivity of TPP resonance frequency can reach 0.0264 THz/K.

The figure of merit for temperature sensing exceeds 150.

TPPs are immune to disorder and can be detected via near-field techniques.

Abstract

We theoretically investigate the application of topological plasmon polaritons (TPPs) to temperature sensing for the first time. Based on an analogy of the topological edge states in the Su-Schrieffer-Heeger model, TPPs are realized in a one-dimensional intrinsic indium antimonide (InSb) microsphere chain. The existence of TPPs is demonstrated by analyzing the topology of the photonic band structures and the eigenmode distribution. By exploiting the temperature dependence of the permittivity of InSb in the terahertz range, the resonance frequency of the TPPs can be largely tuned by the temperature. Moreover, it is shown that the temperature sensitivity of the TPP resonance frequency can be as high as $0.0264~\mathrm{THz/K}$ at room temperature, leading to a figure of merit over 150. By calculating the LDOS near the chain, we further demonstrate that the temperature sensitivity of TPPs is experimentally detectable via near-field probing techniques. This sensitivity is robust since TPPs are highly protected modes immune to disorder and can achieve a strong confinement of radiation. We envisage these TPPs can be utilized as promising candidates for robust and enhanced temperature sensing.