Spatial filtering of light by chirped photonic crystals

TL;DR

This paper introduces a novel spatial filtering technique using longitudinally chirped photonic crystals, enabling improved beam quality and wave directionality through numerical analysis and plane-wave-expansion methods.

Contribution

It presents a new method for spatial filtering of light beams using chirped photonic crystals with varying longitudinal periods, supported by numerical and analytical validation.

Findings

Effective spatial filtering demonstrated through simulations

Enhanced wave directionality achieved with the method

Potential applications in atomic, acoustic, and mechanical wave filtering

Abstract

We propose an efficient method for spatial filtering of light beams by propagating them through 2D (also 3D) longitudinally chirped photonic crystals, i.e. through the photonic structures with fixed transverse lattice period and with the longitudinal lattice period varying along the direction of the beam propagation. We prove the proposed idea by numerically solving the paraxial propagation equation in refraction index-modulated media, and we evaluate the efficiency of the process by plane-wave-expansion analysis. The technique can be applied to filter (to clean) the packages of atomic waves (Bose condensates), as well improve the directionality of acoustic and mechanical waves.