Air Force-funded scientist, Dr. Andrea Alù, has achieved exciting, award-winning results in the advancement of a new class of synthetic materials with military applications ranging from energy harvesting to camouflaging and improved sensing.
Alù, an assistant professor in the Department of Electrical and Computer Engineering at the University of Texas at Austin, is conducting his metamaterials research with a grant awarded by the Air Force Office of Scientific Research via its Young Investigator Program.
"As with all AFOSR-funded research, Alù's work is basic in nature," says Dr. Arje Nachman, AFOSR program manager. "The goal of this particular project is to use a combination of advanced analytical techniques and numerical software to explore new methods for developing exotic composite materials that display properties beyond those found in natural materials."
These types of synthetic materials are more commonly known in the scientific community as metamaterials.
The U.S. Air Force could benefit greatly from the advancement of this field in terms of data processing rates, bandwidths, and size of optical devices on aircraft.
This relatively new field relies on the construction of materials at a macroscopic level, as opposed to the chemical level, which extends the range of electromagnetic responses and, thus, broadens possible uses for Air Force and commercial entities.
Although his grant has just started, Alù has already proposed metamaterial constructs to accomplish two new electromagnetic responses. The first is a metamaterial design that exhibits self-tunable bistable and positive-to-negative index of refraction at optical frequencies and the second is ultrabroadband energy squeezing through narrow plasmonic slits. Both of these results have recently appeared in Physical Review Letters papers.
"Most recently," says Alù, "we have solved a very general theoretical problem related to the causality properties of metamaterial homogenization techniques."
Alù said he believes the field of metamaterials presently suffers from a lack of sufficient theoretical understanding and in order to advance this technology towards its practical applications it is crucial to put forward a solid framework describing metamaterials as bulk homogeneous materials, taking into account their inherent qualities and complex nature.
"We do not describe natural materials as a collection of electrons and atoms, but effectively this is what is still done with metamaterials," explains Alù.
All three of his recent results hold the promise to affect a wide area of metamaterial and electromagnetic research. His work has been influential enough to earn him the URSI Isaac Koga Gold Medal, bestowed every three years by the International Union of Radio Science, for "contributions to the theory and application of electromagnetic metamaterials, in particular the conception of plasmonic-based cloaking, optical nanocircuits, and anomalous propagation and radiation in metamaterials". He will receive the award at the opening ceremony of the XXX URSI General Assembly in Istanbul, Turkey in August.
"At the end of this AFOSR Young Investigator program we envision relevant advancements in the theoretical understanding of the anomalous scattering and radiation properties of metamaterials and of their applications," says Alù.
The far-term goal is to allow future optical devices to work based on propagation, filtering and manipulation of light instead of on electrons, which could lead to smaller and faster devices for the Air Force.
The Air Force Office of Scientific Research, located in Arlington, Virginia, continues to expand the horizon of scientific knowledge through its leadership and management of the Air Force's basic research program. As a vital component of the Air Force Research Laboratory, AFOSR's mission is to discover, shape and champion basic science that profoundly impacts the future Air Force.
Contacts and sources:
by Molly Lachance
Air Force Office of Scientific Research