# Terahertz Wave Absorber Relying on Strontium Titanate and Dirac Semimetal for Dual Adjustability

## TL;DR

A new terahertz absorber using strontium titanate and a Dirac semimetal can switch between absorption modes and sense temperature, offering a versatile platform for terahertz applications.

## Contribution

The paper introduces a dual-tunable terahertz absorber combining strontium titanate and a Dirac semimetal for dynamic absorption and sensing capabilities.

## Key findings

- The device achieves broadband absorption (>90% in 1.347~2.1271 THz) and dual-narrowband absorption under external field control.
- The structure is polarization-insensitive and functions as a high-sensitivity temperature sensor.
- Simulations confirm stable performance under various angles and environmental changes.

## Abstract

Limited by the material response characteristics and structural design, the development of dynamically tunable terahertz absorbers with multi-functional properties remains a major challenge. In this study, a dual-tunable terahertz absorber based on the synergistic integration of strontium titanate (STO) and Dirac semimetal (BDS) is proposed. By utilizing the temperature-sensitive dielectric constant of STO and the electrically tunable conductivity of BDS, the device can realize on-demand switching between a broadband absorption mode (absorptivity >90% in the 1.347~2.1271 THz band) and a dual-narrowband absorption mode under external field excitation. Notably, the centrosymmetric cross-patterned structure on the top layer ensures the polarization insensitivity of the device, and this single structure can also serve as a high-sensitivity temperature sensor. Simulation results verify that the device exhibits stable performance under different incident angles and environmental variations. This study constructs a compact multi-functional device platform integrating dynamic absorption regulation and in situ sensing, which provides a new technical route for the development of intelligent terahertz systems in the fields of terahertz imaging, communication, detection and other related areas.