Pendellosung effect in photonic crystals

TL;DR

This paper reports the experimental observation of the Pendellosung effect in 2D photonic crystal slabs at microwave frequencies, demonstrating periodic intensity modulation due to energy exchange between direct and diffracted beams.

Contribution

First experimental demonstration of the Pendellosung effect in photonic crystals at microwave frequencies, showing thickness-dependent intensity modulation inside and at the surface of the crystal.

Findings

Periodic intensity modulation observed at the exit surface.

Dependence of maximum intensity on slab thickness.

Confirmation of Pendellosung phenomenon in photonic crystals.

Abstract

At the exit surface of a photonic crystal, the intensity of the diffracted wave can be periodically modulated, showing a maximum in the "positive" (forward diffracted) or in the "negative" (diffracted) direction, depending on the slab thickness. This thickness dependence is a direct result of the so-called Pendellosung phenomenon, consisting of the periodic exchange inside the crystal of the energy between direct and diffracted beams. We report the experimental observation of this effect in the microwave region at about 14 GHz by irradiating 2D photonic crystal slabs of different thickness and detecting the intensity distribution of the electromagnetic field at the exit surface and inside the crystal itself.