Design of Ultra-Broadband Metamaterial Absorber from Infrared to Terahertz

Microbolometers can operate in the infrared to terahertz regions and have important applications in high-definition imaging, temperature measurement, and ranging. However, these detectors face technical bottlenecks in the transition region from farinfrared to terahertz, such as weak spectral absorption capability, narrow bandwidth, and manufacturing difficulties. This paper designs a metamaterial absorber composed of Ti-Si-SiO2-Al, which is compatible with standard CMOS processes. The absorber couples different modes of surface plasmon resonance with the intrinsic absorption of the lossy material SiO2. It achieves an average absorption of 79% in the 8–52 μm range and exhibits good polarization and angle insensitivity as well as spectral broadening capabilities. This provides technical support for achieving high-detection-efficiency infrared-to-terahertz microbolometers.

I. Introduction

Detectors in the infrared and terahertz bands play a crucial role in military reconnaissance, environmental monitoring, non-destructive testing, and medical imaging [1]–[2]. Among them, photothermal detectors, represented by microbolometers, operate by absorbing spectral energy and converting it into electrical signals, thus playing a significant role in the infrared and terahertz domains [3].