Tailoring correlations of the local density of states in disordered photonic materials

TL;DR

This paper experimentally investigates how microscopic structures influence local density of states fluctuations in disordered photonic materials, revealing mechanisms for controlling these correlations through material design.

Contribution

It establishes the link between microscopic structure and LDOS frequency correlations, demonstrating independent control of short- and long-range correlations in disordered photonic systems.

Findings

Short- and long-range LDOS correlations are driven by different physical processes.

Single scattering LDOS fluctuations are sensitive to subwavelength features.

Material design can manipulate LDOS statistical properties independently.

Abstract

We present experimental evidence for the different mechanisms driving the fluctuations of the local density of states (LDOS) in disordered photonic systems. We establish a clear link between the microscopic structure of the material and the frequency correlation function of LDOS accessed by a near-field hyperspectral imaging technique. We show, in particular, that short- and long-range frequency correlations of LDOS are controlled by different physical processes (multiple or single scattering processes, respectively) that can be---to some extent---manipulated independently. We also demonstrate that the single scattering contribution to LDOS fluctuations is sensitive to subwavelength features of the material and, in particular, to the correlation length of its dielectric function. Our work paves a way towards a complete control of statistical properties of disordered photonic systems, allowing for designing materials with predefined correlations of LDOS.