Exploiting black phosphorus based-Tamm plasmons in the terahertz region

Area of Science:

• Photonics and optoelectronics
• Materials science
• Terahertz (THz) technology

Background:

• Tamm plasmons are collective electron oscillations at the interface of a metal and a dielectric.
• Black phosphorus (BP) exhibits unique in-plane anisotropy, making it suitable for polarization-sensitive applications.
• Tunable THz devices are crucial for advanced communication and sensing technologies.

Purpose of the Study:

• To investigate polarization-sensitive Tamm plasmons in a multi-layer photonic structure incorporating monolayer black phosphorus.
• To explore the selective excitation and manipulation of Tamm plasmons by tuning the carrier density of black phosphorus.
• To demonstrate the potential of BP-based Tamm structures for THz device applications, such as intensity modulation and polarization division multiplexing.

Main Methods:

• Fabrication of a multi-layer structure consisting of a Bragg mirror, a dielectric spacer, and a monolayer black phosphorus film.
• Excitation and characterization of Tamm plasmons using optical spectroscopy.
• Tuning the carrier density of black phosphorus to control plasmon excitation and polarization properties.
• Analysis of polarization conversion and modulation depth.

Main Results:

• Selective excitation of Tamm plasmons by tuning the black phosphorus carrier density due to its in-plane anisotropy.
• Observation of cross-polarization conversion when the black phosphorus armchair direction is not aligned with the incident plane.
• Demonstration of a BP-based Tamm device as an intensity modulator with high modulation depth (∼100%) and low insertion loss (< -0.55 dB).
• Proposal of a multichannel polarization division multiplexing scheme based on polarization evolution analysis.

Conclusions:

• Monolayer black phosphorus integrated with Tamm plasmons offers a versatile platform for tunable THz devices.
• The anisotropic properties of black phosphorus enable precise control over polarization-sensitive plasmon excitation.
• BP-based Tamm structures show significant promise for high-performance THz modulators and multiplexing schemes, opening new avenues in THz technology.