Nonlinear optical properties and applications of 2D materials: theoretical and experimental aspects

In this review, we survey the recent advances in nonlinear optics and the applications of two-dimensional (2D) materials. We briefly cover the key developments pertaining to research in the nonlinear optics of graphene, the quintessential 2D material. Subsequently, we discuss the linear and nonlinear optical properties of several other 2D layered materials, including transition metal chalcogenides, black phosphorus, hexagonal boron nitride, perovskites, and topological insulators, as well as the recent progress in hybrid nanostructures containing 2D materials, such as composites with dyes, plasmonic particles, 2D crystals, and silicon integrated structures. Finally, we highlight a few representative current applications of 2D materials to photonic and optoelectronic devices

Zero phase delay in negative-refractive-index photonic crystal superlattices

We show that optical beams propagating in path-averaged zero-index photonic crystal superlattices can have zero phase delay. The nanofabricated superlattices consist of alternating stacks of negative index photonic crystals and positive index homogeneous dielectric media, where the phase differences corresponding to consecutive primary unit cells are measured with integrated Mach-Zehnder interferometers. These measurements demonstrate that at path-averaged zero-index frequencies the phase accumulation remains constant and equal to zero despite the increase in the physical path length. We further demonstrate experimentally that these superlattice zero-(n) over bar bandgaps remain invariant to geometrical changes of the photonic structure and have a center frequency which is deterministically tunable. The properties of the zero-(n) over bar gap frequencies, optical phase, and effective refractive indices are well described by detailed experimental measurements, rigorous theoretical analysis, and comprehensive numerical simulations

Theoretical and experimental investigations of easy made fishnet metamaterials at microwave frequencies

In this work, we demonstrate theoretically and experimentally a left handed behaviour of a planar fishnet type metamaterial in the microwave regime. The fabrication procedure based on printed circuit board technology and mechanical micromachining technique is easy, unique and doesn't involve optical lithography. The effective parameters have been extracted using the S parameter retrieval method and show a very good agreement between simulation and experiment. Using finite-element method based simulations and W-band (75 GHz-110 GHz) experiments. We measured a negative index of refraction of −4 at 85 GHz. The demonstrated left handed materials represent a step towards the easy fabrication of metamaterials with a negative refractive index that open a new path for the active manipulation of millimetre wavelengths