Model of light collimation by photonic crystal surface modes

TL;DR

This paper introduces a quantitative model explaining how leaky surface modes on corrugated surfaces of photonic crystals can be used to achieve light collimation, supported by analytical and numerical comparisons.

Contribution

The paper presents a new analytical model for light collimation via surface modes in photonic crystals, validated against numerical simulations.

Findings

Maximum collimation occurs at specific frequencies with surface modes having nonzero real wave numbers.

The dispersion relation of surface modes is characterized for various surface terminations.

Analytical results align well with rigorous numerical simulations.

Abstract

We propose a quantitative model explaining the mechanism of light collimation by leaky surface modes that propagate on a corrugated surface around the output of a photonic crystal waveguide. The dispersion relation of these modes is determined for a number of surface terminations. Analytical results obtained on the basis of the model are compared to those of rigorous numerical simulations. Maximum collimation is shown to occur at frequency values corresponding to excitation of surface modes whose wave number retains a nonzero real part.