Implementation of PT symmetric devices using plasmonics: principle and applications

Area of Science:

• Photonics
• Metamaterials
• Waveguide Optics

Background:

• Parity-time (PT) symmetry in optical devices, characterized by ε((-x)) = ε((x))*, involves coupled systems with gain and loss.
• PT symmetry enables unique phenomena like singular eigenvalue behavior near critical transition points.
• Conventional PT symmetric devices often utilize co-directional coupled waveguides.

Purpose of the Study:

• To transpose the PT symmetry scheme to plasmonic systems with variable gain and fixed loss.
• To leverage plasmonic losses beneficially to achieve a critical regime for optical switching.
• To explore practical implementations using existing and novel plasmonic waveguide structures.

Main Methods:

• Adapting the PT symmetry concept to a configuration with variable gain on one arm and fixed loss on the other.
• Exploiting plasmonic properties, particularly losses, to reach a critical regime.
• Discussing practical implementations based on coupled plasmonic waveguides and the PIROW (Plasmonic Inverse-Rib Optical Waveguide) structure.

Main Results:

• Demonstrated that plasmonic losses can be advantageously used to attain a critical regime.
• Showcased that this critical regime enables optical switching with significantly reduced gain requirements.
• Identified potential for practical realization using advanced plasmonic waveguide designs.

Conclusions:

• The study successfully adapted PT symmetry to plasmonics, utilizing inherent losses for enhanced functionality.
• This approach offers a pathway to efficient optical switching with lower gain demands.
• The proposed methods and structures pave the way for novel plasmonic devices.