Broadband self-collimation in C2 symmetric photonic crystals.

Area of Science:

• Photonics and Optics
• Materials Science

Background:

• Photonic crystals (PhCs) offer unique light manipulation properties.
• Achieving broadband self-collimation with high efficiency and tolerance to misalignment remains a challenge.

Purpose of the Study:

• To design and validate a low-symmetric photonic crystal (PhC) structure for broadband self-collimation.
• To demonstrate high coupling efficiency and robustness against incident angles and misalignment.

Main Methods:

• Analytical calculations including group velocity dispersion and third-order-dispersion.
• Numerical simulations in time and frequency domains.
• Experimental validation using microwave measurements.

Main Results:

• The proposed low-symmetric PhC structure exhibits strong self-collimation over a broadband frequency range.
• High coupling efficiency and beam channeling are maintained even at large incident angles.
• Experimental results confirm self-collimation at millimeter-scale wavelengths, preserving broadband characteristics.

Conclusions:

• The designed PhC self-collimator effectively channels beams with high transmission.
• The structure overcomes potential misalignment issues at the PhC-source interface.
• This work presents a promising solution for robust broadband beam manipulation in photonic devices.