Mapping individual electromagnetic field components inside a photonic crystal

TL;DR

This paper introduces a technique to map the absolute electric field component inside photonic crystals by scanning a spherical scatterer and measuring frequency shifts, validated through microwave experiments.

Contribution

The method enables direct mapping of electromagnetic fields inside photonic crystals with high accuracy, using resonant frequency shifts caused by a subwavelength scatterer.

Findings

Good agreement between measurements and calculations

Effective mapping of electric field component Ez

Applicable at microwave frequencies

Abstract

We present a method to map the absolute electromagnetic field strength inside photonic crystals. We apply the method to map the electric field component Ez of a two-dimensional photonic crystal slab at microwave frequencies. The slab is placed between two mirrors to select Bloch standing waves and a subwavelength spherical scatterer is scanned inside the resulting resonator. The resonant Bloch frequencies shift depending on the electric field at the position of the scatterer. To map the electric field component Ez we measure the frequency shift in the reflection and transmission spectrum of the slab versus the scatterer position. Very good agreement is found between measurements and calculations without any adjustable parameters.