Hyperbolic metamaterials (HMMs), which have an extremely high anisotropy with a hyperbolic dispersion relation, are rising as an innovative method of manipulating light. HMMs have received tremendous interest in photonics for their applicability to various fields such as super-resolution imaging, negative refraction, and emission engineering.
In particular, the development of 2D natural hyperbolic materials, which has recently received much attention, has accelerated the applicability of HMMs. During the past decade, HMMs have shown surprisingly rapid development. Researchers studying HMMs have realized that it is necessary to develop applications by harmonizing HMMs between natural materials and artificial structures.
In a new paper published in eLight, a team of scientists, led by Professor Junsuk Rho from POSTECH, South Korea, Professor Cheng-Wei Qiu from NUS, Singapore, and co-workers have reviewed the recent progress of HMMs and their applications. In this review article, they focused on the overall HMMs from artificially structured HMMs to 2D natural materials and the latest findings that have not been reviewed before. Starting by emphasizing the importance of the implementation of HMMs, they discussed the fundamentals of hyperbolic dispersion, bulk HMMs, and planar 2D HMMs.
Following the fundamental discussions, they reviewed the recent studies in applications of HMMs, including super-resolution optical imaging and nanoscale lithography, light propagation and manipulation, emission engineering, sensors, and absorbers. It is not limited to this, the recently emerging fields of natural HMMs and their recent tremendous progress and further investigation to realize planar hyperbolic applications are reviewed. Finally, perspectives and outlooks of HMMs are given.
The scientists said the importance of hyperbolic metamaterials as:
"The large anisotropy of hyperbolic metamaterials is very important because it can be actively used to pioneer various applications.
"For the development of hyperbolic metamaterials, it was necessary to find a way to maximize efficiency by minimizing the effect of loss. Through the discovery of 2D materials and the development of nanofabrication technology, we believe that technologies applying hyperbolic metamaterials can advance one step further." They added.
"Hyperbolic metamaterials will continue to progress, as they have in the previous decade. Hyperbolic metamaterials are expanding their scope, which will be further widened by combining them with interdisciplinary fields." The scientists forecast.