Learn about the 5 most common types of hyperbolic metamaterials and their unique optical properties, including subwavelength imaging and quantum optics.
Hyperbolic metamaterials (HMMs) are a class of artificially engineered materials that exhibit unique optical properties. They are called hyperbolic because they have a hyperbolic dispersion curve, which is a characteristic feature of these materials. This dispersion curve is responsible for their unique optical properties, such as negative refraction, subwavelength imaging, and enhanced spontaneous emission. In this article, we will discuss the 5 most common types of hyperbolic metamaterials.
Type 1: Metal-dielectric multilayers
One of the most common types of HMMs is metal-dielectric multilayers. These structures consist of alternating layers of metal and dielectric materials. The metal layers are usually thin films of noble metals such as silver or gold, while the dielectric layers are made of materials such as silicon dioxide or titanium dioxide. The thickness of the layers is typically less than the wavelength of light, which allows for the formation of a hyperbolic dispersion curve.
Type 2: Graphene-based HMMs
Graphene is a two-dimensional material that consists of a single layer of carbon atoms. It has unique electronic and optical properties that make it an attractive material for HMMs. Graphene-based HMMs can be fabricated by embedding graphene layers in a dielectric matrix. The hyperbolic dispersion curve in these structures is due to the strong anisotropy of graphene’s electronic properties.
Type 3: Plasmonic HMMs
Plasmonic HMMs are structures that consist of metallic nanoparticles embedded in a dielectric matrix. The nanoparticles can be either spherical or elongated, and their size and shape determine the optical properties of the material. Plasmonic HMMs have a hyperbolic
