Ultrathin tunable terahertz absorber based on MEMS-driven metamaterial

Area of Science:

• Physics
• Electrical Engineering
• Materials Science

Background:

• High-performance tunable absorbers are essential for terahertz (THz) applications like imaging and spectroscopy.
• Metamaterials offer strong position sensitivity in their electromagnetic response.

Purpose of the Study:

• To design and fabricate a highly tunable THz absorber with an ultrathin profile.
• To maximize the tunability range using electrostatic control of suspended membranes.

Main Methods:

• Combining metamaterials with localized modes and suspended, electrostatically driven membranes.
• Utilizing micro-electro-mechanical system (MEMS) technology for device fabrication.
• Characterizing absorption modulation via applied voltage and membrane displacement.

Main Results:

• Achieved ultrathin tunable THz absorbers (thickness ~λ/50).
• Demonstrated absorption tuning from 60% to 80% with fast switching speeds (~27 μs).
• Observed a >200% resonance shift and 65% absorption modulation in the snap-down state.

Conclusions:

• The developed MEMS-based tunable absorber is among the best-performing to date.
• The electrostatic tuning approach offers significant absorption modulation and fast response.
• This technology holds potential for diverse THz applications.