Trapping waves with tunable prism-coupling terahertz metasurfaces absorber.

Area of Science:

• Optics and Photonics
• Metamaterials
• Terahertz (THz) Technology

Background:

• Metasurfaces offer unique electromagnetic properties.
• Perfect absorbers are crucial for various optical applications.
• Terahertz frequencies present unique challenges and opportunities for device development.

Purpose of the Study:

• To experimentally demonstrate a tunable perfect absorber for terahertz frequencies.
• To investigate the role of the central layer and gap in absorption tuning.
• To explore the potential for wide frequency range tailoring and environmental modulation.

Main Methods:

• Fabrication of a corrugated metallic metasurface.
• Utilizing a total internal reflection geometry for THz wave interaction.
• Systematic variation of the central layer and gap to study absorption characteristics.

Main Results:

• Achieved tunable perfect absorption in the terahertz range.
• Demonstrated strong dependence of absorbance on the central layer, enabling tunability.
• Identified an optimal gap for achieving perfect absorption at specific frequencies.
• Showcased wide frequency tunability (0.625-1.499 THz) due to the simple 1D metasurface structure.
• Confirmed that modulation of the surrounding medium's refractive index and loss can alter absorption properties.

Conclusions:

• The corrugated metallic metasurface acts as an effective tunable perfect absorber for THz frequencies.
• The central layer and gap are key parameters for precise control over absorption.
• The demonstrated prism coupling absorber offers a novel approach for modulating absorption characteristics.
• This technology holds potential for advanced applications, particularly in biological sensing.