All-dielectric Resonator Metamaterials
While most metamaterials exploit conducting elements to induce a magnetic response, metallic inclusions can be lossy and scatter strongly. An alternative is to make use of dielectric resonators based on subwavelength pattering in dielectrics, Mie resonant scattering or controlled resonances in displacement currents.
Scattering Control in Compound Aperture Arrays
Aperture and cavity arrays represent a subset of metamaterials that are rich in commercial applications, being that they can be designed to exhibit a wide range of optical properties, have optical properties not possible with other types of metamaterials, and can be manufactured in cost effective ways using commonly used fabrication techniques. Compound Aperture Arrays (CAAs) and Frequency Selective Surfaces (FSSs) have been used in numerous applications in IR focal plane arrays, Light Harvesting Templates, Beam directional control and transparent electrodes for solar cells. This project will include studying a particular aspect concerning both the suppression of back scattered light and enhancement of forward scattered light in periodic CAAs and FSSs.
Development of Modeling and Design Algorithms
Fast and accurate optical modeling tools are essential in device development. Unfortunately, many commercially available algorithms that are based on finite element analysis or finite difference time domain and are slow and prone to errors when applied to electrically large volumes. Professors Michael Fiddy and David Crouse have many years of experience in developing fast, accurate and flexible optical modeling algorithms for plasmonic and photonics crystals, and metamaterials.
High/Zero/Negative Refractive Index Materials
New materials and composite materials with higher permittivities or refractive indices, zero and negative indices of refraction, low loss (e.g. polymers doped with strontium titanate or aligned anisotropic crystallites) for applications at RF, microwave, THz, IR, and optical frequencies.
Materials for Rapid Prototyping
Rapid prototyping is an automated process whereby digital 3D patterns and structures created using computer aided design software are built by either an additive or a subtractive process. The proposed project will focus on developing the engineered nano-particles that have enhanced or tailored electromagnetic responses so that rapid prototyping processes can be exploited to make a precise 3D metamaterials structures with engineered “meta-atoms” doping.
Metamaterials Building Blocks
Development of manufacturable processes for low cost metamaterial “building blocks” (e.g. Lego-like assembly of spatially variant meta-structures).
Multilayer Thin Film Development
Development of MBE, PECVD techniques, low cost high volume 3D metamaterials, and tunable metamaterials (writing, imprinting, self-assembly, UV-curable polymers).
Next Generation Metallic Resonator Metamaterials
Development of next generation metallic metamaterials, resonator metamaterials, and coupled resonators with reduced loss, extreme optical index values, higher frequency resonances and broader bandwidths.
Process Development of Composite Materials
Precision laser micromachining is a potential alternative fabrication method to traditional metamaterial fabrication. For laser machining processes, the laser beam is focused in order to concentrate the power to a level that is capable of removing or changing material. The minimum feature size is therefore proportional to the size of the focused laser beam. In this proposed research, we will investigate to reduce the smallest feature size of the precision laser micromachining technology into 100 nm range to demonstrate the proof-of-concept super-resolution laser lithography.
Tools for Characterization of Metamaterials
Extensive facilities exist at each of the universities for materials testing and characterization. The major concern with metamaterials of the type discussed in these projects will be losses and scattering as a function of bandwidth. Microwave and optical characterization of materials can be made with high precision. Micro- and nano-structures can be probed with in-house atomic force microscopy, scanning electron microscope and transmission electron microscopy.