Disorder in Photonic Structures induced by random layer thickness

The investigation of the differences between ordered and disordered materials (in the hundreds of nanometer lengthscale) is a crucial topic for a better understanding of light transport in photonic media. In this work, we study the light transmission properties of disordered one dimensional photonic structures in which disorder is introduced by a random variation of layer thickness. The structures have been fabricated by rf-sputtering technique. The transmission spectrum of the disordered structure has been carefully simulated by taking into account the refractive index dispersion of silicon dioxide and titanium dioxide, resulting in a very good agreement between the experimental data and the simulations. We found that the transmission of the photonic structure in the range 300 - 1200 nm is lower with respect the corresponding periodic photonic crystal. This study envisages the use of disordered one dimensional photonic structures for the modelization and realization of broad band filters. Acknowledgments The research activity was performed in the framework of CNR-PAS joint project Nanostructured systems in opal configuration for the development of photonic devices (2014-2016) and Progetto Premiale "Strutture risonanti per la rivelazione di biomarkers precursori della sepsi". The COST Action MP1401 Advanced fibre laser and coherent source as tools for society, manufacturing and life science is also acknowledged.