Radiation is an important energy transfer process that has wide applications in energy harvesting, production, and utilization. Radiation energy transfer can be accomplished by far-field radiation, where radiative surfaces are separated by a distance longer than the radiation wavelength (typically several to tens of micrometers) and near-field radiation, in which the surfaces are separated by a distance shorter than the radiation wavelength. In this project, engineered surfaces with specifically designed very small (microscale) patterns, called meta-surfaces, are studied to achieve specific far-field radiation properties and to enhance near-field radiation for applications such as thermal-photovoltaics in solar energy harvesting. The project aims to generate a wealth of scientific and engineering knowledge to advance the fundamentals and engineering of radiation energy transfer. It can also be applied to other fields of science and engineering, including high resolution imaging, sensing, and infrared radiation sources. In addition, the project provides education and training to the next generation scientists and engineers, broadens participation of underrepresented groups, and increases public awareness of radiation science and technology.
This project designs novel meta-surfaces that are advantages for the desired radiation properties and transfer processes. Specifically, meta-surfaces capable of enhancing the magnetic radiation field in addition to the electrical radiation field are studied. This approach provides the design space for manipulating both electric and magnetic properties to achieve desired far- and near-field performances, while using relatively simple two-dimensional meta-surface structures. Advanced experimental techniques are used in this project, including near-field radiation measurements with surface separation distances of tens of nanometers, FTIR (Fourier Transform Infrared spectroscopy) coupled with near-field scanning optical microscopy, FTIR near-field emission microscopy, and far-field FTIR spectroscopy. These studies provide a complete micro-to-macro spectroscopic picture of the designed meta-surfaces to validate the design theories, therefore, to advance far- and near-field radiation research and facilitate their applications.
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.
