Tunable and ultra-narrowband multifunctional terahertz devices using anisotropic graphene based hyperbolic...

Area of Science:

• Photonics and Metamaterials
• Terahertz (THz) Technology
• Graphene-based Devices

Background:

• Graphene's unique properties make it suitable for advanced optical applications.
• Metamaterials offer novel ways to control electromagnetic waves.
• Terahertz technology requires efficient and tunable devices.

Purpose of the Study:

• To propose and analyze a novel anisotropic graphene-based hyperbolic metamaterial (AGHMM) structure.
• To demonstrate the application of this structure in various THz devices.
• To highlight the tunability and high performance achievable with the proposed design.

Main Methods:

• Numerical simulation using the transfer matrix method (TMM).
• Analysis via effective medium theory (EMT).
• Three-dimensional finite-difference time-domain (3D-FDTD) simulations.
• Investigation of optical Tamm states (OTS) at interfaces.

Main Results:

• A sharp defect mode originating from OTS was observed.
• Demonstrated tunable electro-optical modulators with high extinction ratio (24.75 dB) and low loss (0.05 dB).
• Achieved tunable polarizers with record high polarization extinction ratios (PERs) up to 76.8 dB.
• Realized multiband tunable filters with high quality factors (up to 75314).
• Developed a narrowband perfect absorber with 99.8% absorption and ultra-narrow FWHM (0.00055 THz).

Conclusions:

• The proposed AGHMM structure is a versatile platform for THz applications.
• Device performance is tunable via incident angle and graphene chemical potential.
• The achieved results represent significant advancements in THz device technology.