Discrete negative refraction in photonic crystal waveguide arrays

Area of Science:

• Photonics and Optics
• Condensed Matter Physics
• Waveguide Optics

Background:

• Photonic crystal waveguide arrays offer unique light manipulation properties.
• Anomalous refractive effects, such as negative refraction, are of significant interest for novel optical devices.
• Understanding interface phenomena is crucial for controlling light propagation in engineered photonic structures.

Purpose of the Study:

• To systematically analyze anomalous refractive effects at interfaces between photonic crystal waveguide arrays.
• To establish a predictive method for negative refraction in these systems.
• To investigate the influence of coupling coefficients on refractive properties.

Main Methods:

• Theoretical analysis of light propagation at interfaces.
• Numerical simulations of coupled photonic crystal waveguides.
• Systematic variation of waveguide parameters and coupling strengths.

Main Results:

• Observed discrete negative refraction at the interfaces.
• Demonstrated that the sign of the coupling coefficient between adjacent waveguides dictates negative refraction.
• Showed that this prediction is independent of the propagation handedness.

Conclusions:

• The sign of the coupling coefficient is a robust indicator of negative refraction in photonic crystal waveguide arrays.
• This finding simplifies the design and prediction of optical behavior in such systems.
• Offers a pathway for developing advanced optical components based on controlled negative refraction.