This project conducts research into a new class of artificial nonlinear nanophotonic materials, which makes use of the investigators ability to use nanofabrication in conjunction with intrinsic materials properties to tailor the optical response of those metamaterials. The main challenges towards a comprehensive understanding and experimental realization of nonlinear optical properties of metamaterials are that a theory of surface and bulk nonlinear optics of metamaterials is yet to be developed, and a practical means to fabricate and test such a theory is missing as well. The central rationale for this collaboration is that it matches a strong UK group at University College London with demonstrated theoretical capabilities in nonlinear optics and focused-ion-based fabrication capabilities, with a US group at Columbia University with a demonstrated record of integrated and plasmonic fabrication, optical testing, and materials preparation. Interactions with the Brookhaven National Laboratory (BNL) Nanocenter as well as that with the London Centre for Nanotechnology are also important for fabrication. The materials of interest include periodic nanostructures in ferroelectrics and in plasmonic metals. Several nanophotonic structures are examined, including photonic crystals, negative index metamaterials, and tuning of these materials using electrooptical effects in thin membranes. New theoretical aspects are also examined, including nonlinear effects in plasmonic scattering and plasmonic enhancement of optical absorption in thin films.
The research undertaken here has several areas of broad impact. First, it fosters an interdisciplinary examination of the fundamental materials science of artificial nonlinear metamaterials, including fabrication and growth, materials physics, optical physics, and theory. Second, it enables two groups in the US and the UK, with a strong history of interactions and complementary expertise and capabilities, to collaborate. This work involves the opportunity for both graduate and undergraduate students to collaborate and travel in an international setting. Third, the project has concrete plans and procedures to seek out recruitment of diverse student collaborators via four outreach talks to undergraduates at Columbia University and one outreach talk at University College London, UK. It also enables active participation of students in the undergraduate research opportunities program (UROP) at Columbia. Fourth, the project enables students to collaborate via extended visits and shorter trips with a major US National Laboratory, i.e. Brookhaven, in their new Nanocenter, as well as the London Centre for Nanotechnology.
Intellectual Merit: This Materials World Network Program has focused on research into new classes of artificial optically nonlinear photonic materials, which rely on nano-patterning and –fabrication, in conjunction with intrinsic materials properties, to produce new functionality for these optical materials. These materials are sometimes called metamaterials since they use ordered small features, only nanometers in dimension, of composite materials using dielectrics and metals to give the new material otherwise obtainable optical properties. Our research team is built on an international group to solve the challenges in realizing these new metamaterials structures and devices; these challenges include developing new theoretical and experimental methods as well as exploring new materials combinations. Our team has realized new methods to simulate complex nonlinear optical behavior, new approaches to make crystal structures, which enhance nonlinear conversion of one optical wavelength into a second wavelength, new experimental approaches to pattern periodic dielectric variation in ferroelectric materials, and finally new techniques to design and fabricate metallodielectric metal materials, which have anisotropic optical polarization response. The program has combined synergistically four collaborating groups, two in the UK, one in the US, one in Croatia, and one in German to carry out this ground-breaking research, which is described in detail in our scientific papers and in our talks and presentations. The central rationale for this collaborative group was that it matched a strong UK group with demonstrated theoretical capabilities in nonlinear optics and with focused-ion-based fabrication capabilities with a US group with a demonstrated record of integrated optics and plasmonic fabrication, optical testing, and materials preparation. Interactions with the Brookhaven National Laboratory (BNL)) Nanocenter, via their user program, as well as that in London Centre for Nanotechnology was also important for fabrication. Broader Impacts: The research has had several areas of broad impact. First, it has fostered an interdisciplinary examination of the fundamental materials science of artificial nonlinear metamaterials, which includes fabrication and growth, materials physics, optical physics, and theory, including detailed electromagnetic simulation of metallo-dielectric, SOI-based materials, and ferroelectric materials. These materials are important for future advanced applications in optical data handling, displays, and imaging. Second it has enabled two groups in the US and the UK, as well as lesser programs with groups in Croatia and Germany, with a strong history of interactions and complementary expertise and capabilities to extend and strengthen their collaboration. Third, the program has involved interaction and student involvement with women and minority scientist collaborators. We have also involved woman students in our research program via summer undergraduate students. We have also carried out a series of outreach talks to undergraduate students at Columbia and at University College London, UK. Fourth, our project has enabled our students to collaborate, and thus extend their education, via extended visits and shorter trips with major US and UK national laboratories as well as unique facilities in Croatia and Germany.
