These fabrication methods demonstrate the potential, both present and future, of 3D printing to expand the range of geometric designs and material composites that lead to devices with novel optical properties. In one case, the researchers drew inspiration from the compound eye of a moth to create a hemispherical device that can absorb electromagnetic signals from any direction at selected wavelengths.
Metamaterials extend the capabilities of conventional materials in devices by making use of geometric features arranged in repeating patterns at scales smaller than the wavelengths of energy being detected or influenced. New developments in 3D printing technology are making it possible to create many more shapes and patterns of metamaterials, and at ever smaller scales. In a study, published in the journal Microsystems & Nanoengineering, researchers at the Nano Lab at Tufts describe a hybrid fabrication approach using 3D printing, metal coating and etching to create metamaterials with complex geometries and novel functionalities for wavelengths in the microwave range.
In one example, the researchers created an array of tiny mushroom shaped structures, each holding a small patterned metal resonator at the top of a stalk. This particular arrangement permits microwaves of specific frequencies to be absorbed, depending on the chosen geometry of the "mushrooms" and their spacing. Use of such metamaterials could be valuable in applications such as sensors in medical diagnosis and as antennas in telecommunications or detectors in imaging applications.