Observation of backscattering-immune chiral electromagnetic modes without time reversal breaking

Area of Science:

• Photonics
• Condensed Matter Physics
• Wave Phenomena

Background:

• Time reversal invariant systems offer potential for robust wave propagation.
• Photonic crystals provide a versatile platform for controlling light.
• Chiral phenomena in wave systems can lead to unique transport properties.

Purpose of the Study:

• To propose and demonstrate a strategy for robust transport in time reversal invariant photonic systems.
• To investigate the immunity of chiral guided modes to scattering from defects.
• To explore the feasibility of realizing such robust transport in practical, nonmagnetic materials.

Main Methods:

• Numerical simulations of wave propagation in a three-dimensional dielectric photonic crystal.
• Experimental verification using microwave frequencies.
• Analysis of a chiral guided mode within a channel structure.

Main Results:

• A chiral guided mode within a photonic crystal channel was identified.
• This mode demonstrated immunity to scattering from inserted metallic or dielectric square patches.
• The transport remained robust despite intentional channel blockage.

Conclusions:

• Chirality in photonic systems enables robust wave transport, even in the presence of defects.
• This robust transport can be achieved in nonmagnetic dielectric materials without external fields.
• The findings pave the way for developing resilient photonic devices and communication systems.