Emissivity Engineered Infrared Materials, 3-Dimensionally Patterned by Two Photon Lithography

The objective of this program is to make infrared pigments whose emissivity can be controlled. The principal approach we have taken is to make 3-dimensionally microstructured metallodielectric materials by two-photon lithography in photoresist, and back-filling with metals. In this program we demonstrated that we can quickly and efficiency fabricate 3<1 microstructures in photoresist using a diode pumped Ti-sapphire modelocked laser in combination with a mechanical scanning technology. Metal back-filling of copper into porous membranes was accomplished using electrodeposition methods and complementary fundamental studies were able to establish some of the details of this metallization process. Initial results using self-assembly methods for metallization were also obtained. Another approach for producing 3<1 metallo-dielectric structures, based on the direct writing of silver structures by two-photon processes, was also demonstrated. In addition to experimental work, this program included computational activities. An analysis of the resolution limits of two-photon lithography showed that a doubling of resolution was possible. Other studies in this program included the design of frequency selective grid structures and an analysis showing that 1-d interference filters can be used to achieve a broad reflection spectrum.