Tunable tapered waveguide for efficient compression of light to graphene surface plasmons

Area of Science:

• Optoelectronics
• Nanophotonics
• Materials Science

Background:

• Dielectric-graphene-dielectric (DGD) structures are key for infrared optical devices due to their small size and low energy dissipation.
• Graphene's optical properties are tunable via chemical potential modulation using biased voltage.
• Existing end-fire excitation methods for graphene surface waves suffer from low efficiency due to wavevector mismatch.

Purpose of the Study:

• To propose and analyze a novel dielectric-semiconductor-dielectric (DSD) tapered waveguide for efficient excitation of surface waves on DGD structures.
• To demonstrate magnetic tunability for controlling surface wave excitation.
• To overcome the limitations of existing excitation methods for infrared surface waves on graphene.

Main Methods:

• Design and theoretical analysis of a DSD tapered waveguide structure.
• Electromagnetic simulations to verify the proposed design and performance.
• Investigation of magnetic field's effect on surface wave excitation efficiency.

Main Results:

• The proposed DSD tapered waveguide enables efficient excitation of surface waves on DGD structures.
• Efficient excitation is achieved across various graphene chemical potentials and incident frequencies.
• Control is achieved by simply adjusting the external magnetic field applied to the DSD waveguide.

Conclusions:

• The DSD tapered waveguide offers an effective solution for efficient surface wave excitation on DGD structures in the infrared.
• Magnetic tunability provides a versatile method for controlling surface wave excitation.
• The use of naturally available materials and the demonstrated efficiency pave the way for practical applications in surface wave-based devices.