One of the most rapidly advancing fields in modern optics is centered on the production of beams of light that are structured over wavelength-scale dimensions. The properties of variously structured beams, and their forms of interaction with nanostructured media, are indeed emerging as a new frontier in modern optics. The establishment of sound concepts and proven methods for engineering designed forms of wavefront or polarization structures affords numerous opportunities to exploit previously overlooked degrees of freedom, which are associated with access to the spatial profile of the wave vector and polarization. Optical vortices and vector beams are two of the most prominent examples. Many of the novel aspects of structured light beams carry over into the quantum realm, where the character of distinct photon interactions becomes evident. Moreover, recent developments in the field of optical nanostructures, metamaterials, and transformation optics have unlocked methods that can be used to achieve unprecedented control over light propagation and the possibilities for “engineering” space for light propagation. The synergy of structured light with “engineered” structured optical materials appears likely to open a genuinely new paradigm in optical physics.

This special issue includes 10 contributed papers focused on the most recent advances in structured light, structured media and their synergy, targeting novel interactions of structured light with matter, developments in fundamental theory, and a wide range of real world applications. It is a bit invidious to select specific papers, but the following may serve to illustrate the breadth of topic. For example, in the context of dynamic singular optics—itself a new and rapidly developing branch of singular optics—Soskin et al. investigate topological singular chain reactions in dynamic speckle fields. Their reported experiments provide evidence that dynamic topological speckle fields develop through loop and chain trajectories in accordance with pair nucleation and the annihilation of optical singularities. In connection with the orbital angular momentum that always accompanies such field singularities, Karimi and co-authors report a theoretical and experimental study of the limitations of one of the most widely used technique used for measuring the orbital angular momentum of light beams. The paper by Rumala et al. presents a detailed study of multiple optical vortex states achieved with a spiral phase plate etalon, and, as a promising new environment for the manipulation and applications of structured light, Scalora et al. discuss the optics of nanoplasmonic media, developing a fundamental quantum mechanical approach to describe nonlinear quantum tunneling effects in such media. We believe that these and all the many other remarkable contributions effectively represent the cutting edge of new developments in modern optics, at the intersection of structured light and structured materials, paving the way for new research.