EXCELLENCE IN RESEARCH: QUANTUM NANOPHOTONICS WITH PERIODIC CARBON NANOTUBE ARRAYS

NONTECHNICAL SUMMARY

This award supports theoretical and computational research and education to advance understanding of how the spectrum of light from atoms, molecules, quantum dots, and other nanostructures is affected by interaction with a substrate. The PI will focus on a substrate that is made of an array of closely packed nanoscale cylinders of carbon with diameters on the scale of nanometers and up to about a centimeter in length. These carbon nanotubes resemble rolled 'chicken wire' on the nanoscale with carbon atoms at the vertices. By adjusting the carbon nanotube structure, the electronic properties of the substrate can be controlled and so the properties, including the optical properties, of the nearby molecule or quantum dot, including how they emit light, can also be controlled. The PI will use a theoretical approach based on quantum mechanics, solid state physics, and optics combined with computer simulations to understand qualitatively and quantitatively how this system may be used for molecular sensing, controlling chemical reactions, as a sensitive probe of the electromagnetic and optical properties of molecules and nanostructures, tunable light sources, and other possible applications.

This project is aimed to provide theoretical understanding of capabilities and practical guidance for the experimental development of these closely packed periodically aligned carbon nanotube arrays - ultrathin multifunctional metasurfaces - a new flexible advanced photonic metamaterial platform with the near-field characteristics adjustable on demand by means of the nanotube diameter, chirality and periodicity variation.

This award supports training a new generation of scientists and engineers capable of harnessing the opportunities presented by nanomaterials for new technologies and to better understand the world around us. This theory and simulation project will help to shape the graduate curriculum of the Department of Mathematics and Physics at North Carolina Central University, the nation's first state-supported public liberal arts college for African Americans. Relevant graduate courses offered by the Department will be revised and enhanced to include aspects of low-dimensional carbon nanomaterials inspired in part by the research. Advanced graduate students will have opportunities to participate in cutting-edge research, attend research symposia, present seminars, and develop Master's theses. Increased exposure of students to this exciting and rapidly expanding field of nanotechnology will lead to increased participation of underrepresented minority students in scientific careers and in graduate studies in scientific fields. This project will thus contribute to broadening the diversity of the next generation of scientists, researchers and engineers and to directly address national needs in the areas of Science, Technology, Engineering and Mathematics.

NONTECHNICAL SUMMARY

This award supports theoretical and computational research and education to advance the fundamental theoretical understanding of near-field interactions and quantum processes in planar closely packed periodically aligned carbon nanotube arrays. Intrinsic mechanisms of plasmon enhanced spectroscopic detection, molecular sensing, and control will be studied using rigorous methods of theoretical solid-state physics, quantum electrodynamics and quantum optics, combined with computer modeling and simulations. Carbon nanotubes have been successfully integrated into miniaturized electronic, electromechanical, and chemical devices, scanning probes, and into nanocomposite materials, offering extraordinary stability, flexibility, and precise tunability of their physical properties. Recent progress in the fabrication of closely packed periodically aligned carbon nanotube arrays opens new opportunities and challenges to develop new material functionalities with these highly anisotropic ultrathin metamaterial structures. Plasmonic bands form because of the nanotube array periodicity, and so the planar closely packed periodic carbon nanotube arrays should behave as epsilon-near-zero plasmonic metasurfaces in the near field while remaining strong light absorbers and polarizers in the far field. The spatial anisotropy and the periodic in-plane transverse inhomogeneity of the array make the electromagnetic field in its vicinity anisotropic and nonlocal, adding both extra flexibility in designing the arrays with desired electromagnetic properties and extra challenges in developing the problem theoretically. Plasmon generated near fields can strengthen weak electronic and/or vibrational molecular transitions to enhance low-energy absorption, scattering and chemical reactivity features for molecules near the planar nanotube array. This project will be focusing on the quantum theory development for near-field electromagnetic absorption and far-field reflection/scattering by extrinsic emitters coupled to spatially anisotropic, periodically inhomogeneous, dissipative magneto-dielectric environment in close proximity to the periodic carbon nanotube array. Process cross-sections will be derived in universal forms suitable both for the experimental interpretation and for the practical guidance of the experimental development to uncover novel functionalities of the planar periodic carbon nanotube arrays as a new flexible advanced photonic metamaterial platform with near-field characteristics adjustable on demand by means of the nanotube diameter, chirality, and array periodicity. Particular practical applications of this theoretical effort include: (a) efficient Surface Enhanced Raman Scattering substrate development for single atom/ ion/molecule detection, trapping and manipulation; (b) precision control of spontaneous emission, absorption and scattering by atomic type emitters trapped near the planar nanotube array metasurfaces; (c) near-field control of molecular chemical reactivity and peculiar Casimir-Polder forces in close proximity to the periodic carbon nanotube arrays.

This award supports training a new generation of scientists and engineers capable of harnessing the opportunities presented by nanomaterials for new technologies and to better understand the world around us. This theory and simulation project will help to shape the graduate curriculum of the Department of Mathematics and Physics at North Carolina Central University, the nation's first state-supported public liberal arts college for African Americans. Relevant graduate courses offered by the Department will be revised and enhanced to include aspects of low-dimensional carbon nanomaterials inspired in part by the research. Advanced graduate students will have opportunities to participate in the cutting-edge research, attend research symposia, present seminars, and develop Master's theses. Increased exposure of students to this exciting and rapidly expanding field of nanotechnology will lead to increased participation of underrepresented minority students in scientific careers and in graduate studies in scientific fields. This project will thus contribute to broadening the diversity of the next generation of scientists, researchers and engineers and to directly address national needs in the areas of Science, Technology, Engineering and Mathematics.

This award is made on a proposal to the Historically Black Colleges and Universities Undergraduate Program (HBCU-UP) under the HBCU Excellence in Research track. Funds from the HBCU-UP program in the Division of Human Resource Development in the Human Resource Development Directorate and from the Division Materials Research in the Mathematical and Physical Sciences Directorate.

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.