Metasurface absorber with ultra-thin thickness designed for a terahertz focal plane array detector

Area of Science:

• Electromagnetics and Optics
• Materials Science
• Detector Technology

Background:

• Terahertz (THz) waves (0.1–10 THz) bridge millimeter waves and infrared light.
• Metasurface absorbers are key components for enhancing THz detection.
• Focal Plane Array (FPA) detectors require efficient signal coupling and thermal isolation.

Purpose of the Study:

• To propose an ultra-thin metasurface absorber for terahertz FPA detectors.
• To achieve high absorptance and polarization insensitivity.
• To ensure thermal isolation for improved imaging.

Main Methods:

• Design and simulation of an ultra-thin metasurface absorber.
• Unit cell design with air gaps for thermal isolation.
• Analysis of absorptance across a range of frequencies, polarizations, and incidence angles.

Main Results:

• Achieved absorptance >80% from 4.46 to 5.76 THz.
• Metasurface thickness is only 1.12 µm (0.018 λ).
• Stable absorptance for various polarizations and incidence angles (±30°).

Conclusions:

• The proposed ultra-thin metasurface absorber is ideal for terahertz FPA detectors.
• Features include high absorptance, polarization insensitivity, and thermal isolation.
• Enables highly efficient coupling of terahertz signals in FPA detectors.