Engineered disorder in photonics

Disorder, which qualitatively describes some measure of irregularities in spatial patterns, is ubiquitous in many-body systems, equilibrium and non-equilibrium states of matter, network structures, biological systems and wave–matter interactions. In photonics, the introduction of order and disorder for device applications has traditionally been treated separately. However, recent developments in nanofabrication and design strategies have enabled the use of materials that lie between the extremes of order and disorder that can yield innovative optical phenomena owing to their engineered disordered patterns. Here, we review recent achievements in the emerging field of engineered disorder in photonics by outlining milestones in the control of the spectrum, transport, wavefront and topology of light in disordered structures. We show that engineered disorder has begun to transform the traditional landscape of photonics by introducing a greatly enhanced design freedom and, hence, has great potential for the rational design of the next generation of materials.