Stabilized Dirac points in one-dimensional non-Hermitian optical lattices

Area of Science:

• Condensed Matter Physics
• Topological Photonics
• Non-Hermitian Systems

Background:

• Dirac points (DPs) are crucial in condensed matter physics, typically found in Hermitian systems.
• Non-Hermitian systems offer unique phenomena but often lack stability.
• Controlling light propagation in optical lattices is key for photonic devices.

Purpose of the Study:

• To demonstrate stable Dirac points (DPs) in low-dimensional non-Hermitian optical lattices.
• To explore the role of pseudo-Hermiticity and charge-conjugation parity symmetry in stabilizing DPs.
• To investigate the potential for controlling light dynamics and energy stability.

Main Methods:

• Utilizing coupled Su-Schrieffer-Heeger chains in an optical lattice.
• Leveraging non-Hermiticity and specific symmetry constraints (pseudo-Hermiticity, charge-conjugation parity).
• Analyzing band structures and eigenmode properties at spectral degeneracies.

Main Results:

• Stable non-Hermitian Dirac points (DPs) were successfully demonstrated.
• DPs were shown to be topological charges, stable against variations in dissipation.
• Beam splitting with stable power evolution was observed around the DPs.
• DPs can evolve into nodal rings in two-dimensional systems.

Conclusions:

• Non-Hermiticity, combined with specific symmetries, can stabilize topological features like DPs.
• The findings offer a pathway for robust light control in photonic systems.
• This research has implications for designing stable optical devices and manipulating light flow.