# Direct Wide-angle Measurement of Photonic Band- structure in a Three-dimensional Photonic Crystal using Infrared Fourier Imaging Spectroscopy

## TL;DR

This paper introduces a method using infrared Fourier imaging spectroscopy to directly measure and visualize the photonic band-structure of three-dimensional photonic crystals, enabling detailed analysis of their optical properties.

## Contribution

The authors develop a wide-angle spectroscopy technique that accurately measures the band-structure of 3D photonic crystals in the infrared range, including high-symmetry directions.

## Key findings

- Successful measurement of band-structures along key symmetry directions
- Good agreement between experimental reflectance patterns and simulations
- Technique applicable for characterizing photonic structures in the infrared

## Abstract

We propose a method to directly visualize the photonic band-structure of micron size photonic crystals using wide angle spectroscopy. By extending Fourier Imaging Spectroscopy sensitivity into the infrared range we have obtained accurate measurements of the band-structures along the high-symmetry directions (X-W-K-L-U) of polymeric three-dimensional rod-connected diamond photonic crystals. Our implementation also allows us to record single-wavelength reflectance far field patterns showing a very good agreement with simulations of the same designs. This technique is suitable for the characterization of photonic structures working in the infrared and in particular, to obtain band-structure information of complete photonic band gap materials.

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Source: https://tomesphere.com/paper/1703.00711