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Center for Metamaterials (CfM)

Center Overview

The Center for Metamaterials (CfM) designs, fabricates, and tests a wide range of metamaterials. Its mission is to advance fundamental and applied metamaterials research, development, and technology transfer through strong collaborations between industry and universities. There is strong industry interest in metamaterials, as they are being used to develop new or higher-performing optical, electronic, and acoustic devices.

Metamaterials are patterned and/or composite materials that exhibit effective permittivity, permeability, or refractive index properties not found in nature. Their properties are commonly the result of resonant phenomena arising from the subwavelength-scaled elements forming those patterns or composites. The smaller these elements are with respect to the wavelength of the electromagnetic radiation, the better the metamaterial satisfies effective medium criteria and the more accurately they can be treated as a genuinely new material. Such materials have the potential to provide index values - very large, less than unity, or negative - with broad applications.

Universities

Clarkson University
University of North Carolina, Charlotte

View Center Website

Center Personnel

Zijie Yan
Center Staff
+1 315 268 6475
zijieyan@email.unc.edu

Ishwar Aggarwal
Center Staff
+1 704 687 1888
iaggarwa@uncc.edu

Research Focus

Active metamaterials

CfM explores this rich area of fundamental research of metamaterial, which is characteristically defined by its active composition of the host material. "Active" refers to the material properties that exhibit either optical gain under pumping, strong material nonlinear properties, or both.

Active metasurfaces

Metamaterials researchers have developed novel metallic feature structures, metasurfaces, that allow for local control of the phase as an optical beam is transmitted through a surface. This project is investigating these metasurfaces using a low-cost, rapid-development approach to increase the efficiency of the refraction, develop designs that allow for pixilated arrays of flat lenses, and investigate tuning concepts that would allow for the steering of microwave and infrared beams.

Design and fabrication of low-loss low-index optical metamaterials

A new and rigorous theory that goes well beyond well-known mixing rules has been used to predict specific particle properties that would lead to a composite metamaterial having a desired refractive index, such as less than unity. Modeling based on this method and the development of processes and procedures to make and characterize coated nanoparticles are in progress.

Infrared Mueller matrix imaging of dielectric metamaterials

Recent advances in three-dimensional laser direct writing enable the fabrication of dielectric metamaterials composed of constituents with virtually arbitrary geometry at the nanometer scale. But analysis of such metamaterials in the infrared spectral range is still lacking. In this project, CfM uses variable angle of incidence ellipsometry and near normal incidence ellipsometry to characterize infrared metamaterials composed of subwavelength dielectric structures.

Metasurface design

This project is developing and validating a design tool for bulk metamaterials that considers coupling effects between nanostructures. It is based on a building block of resonators for each nanostructure referenced in a database to compile the desired design structure.

Orbital angular momentum (OAM) fiber

This project focuses on generating, detecting, and sorting OAM modes. In this project, CfM takes what it has learned in past projects combined with knowledge in the field of fiber gratings and aims to develop a fiber grating that filters for OAM mode.

Sorting uniquely identical spherical resonators by light forces

CfM is developing a disruptive technology of sorting microspheres with extraordinary high level of uniformity of their whispering gallery mode resonances. The proposed method is based on work done by CfM showing that a focused laser beam exerts optical force on microspheres traversing the beam.

Terahertz (THz) metamaterials

CfM has discovered that THz form-birefringence can be induced in subwavelength structures fabricated from methacrylates using stereolithographic fabrication. These results provide a new avenue for the fabrication of highly anisotropic THz metamaterials and their use for THz sensing and imaging applications.

Awards

2052745

IUCRC Phase III University of North Carolina at Charlotte: Center for Metamaterials (CfM)

The Center for Metamaterials (CfM) at University of North Carolina in Charlotte (UNCC) focuses on the research and development of metamaterials. Metamaterials are man-made materials that and offer new ways to control the flow of light and enable sophisticated filtering and detection. Metamaterials are making an impact on sensing, imaging, antennas, and energy harvesting. The Center's primary focus is on optical, infrared and radar applications of metamaterials. The projects conducted within the CfM are developed collaboratively. The research is conducted by graduate and undergraduate students under the guidance of CfM professors and Center members. Students, many of whom come from under-represented groups in science and engineering, obtain mentorship from the industry members; this mentorship prepares them for professional careers after graduation. The CfM contributes to the workforce development of trained and highly skilled scientists and engineers. The faculty and students at CfM work in close collaboration with members (industry and government) to develop new knowledge, new materials' capabilities, and software tools for the fundamental understanding and practical design of metamaterials. The technology roadmap provides a framework for the clustering of project objectives into more specific goals. To ensure the long-term success and viability of the Center, efforts focus on metamaterials research for a broad range of commercially relevant applications. CfM goals are to better understand and exploit the new properties associated with these structured materials. Within the CfM there are many foundational scientific questions to be addressed, concerning understanding and modeling the physical processes that occur when electromagnetic or mechanical waves interact with subwavelength sized structures. Resonant behavior combined with effective medium descriptions can be used to predict unusual material properties such as negative or zero refractive index. Exploiting resonant behavior in subwavelength elements, surface patterns, and composites, all demand more complete descriptions and a deeper understanding of field-matter interactions. The emerging long-term challenge is to engineer material properties that are low loss, broadband, tunable, low-cost, and manufacturable at scales relevant for technological applications. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria. Read More >

The opinions, findings, and conclusions or recommendations expressed are those of the Center author(s) and do not necessarily reflect the views of the U.S. National Science Foundation.