Field-effect Tunable Titanium Nitride Epsilon-Near-Zero Metasurfaces for Dynamic Manipulation of Thermal Emission
Abstract
Controlling thermal emission/radiation is important for thermal imaging, gas/chemical sensing, and energy applications. In particularly, one of the major challenges for energy harvesting is to absorb the photon energy within a thin semiconductor film and to minimize the thermal energy lost by the solar cell. Over 60 percent of incident solar energy is lost because of thermalization for radiation above the bandgap and non-absorption for radiation below the bandgap. Therefore, it remains a grand challenge to develop techniques to efficiently control, enhance, and redirect thermal radiation to recycle thermal energy for thermal sensing/imaging and thermophotovoltaic devices. Optical metasurfaces, which are arrays of subwavelength anisotropic light scatterers (optical antennas) that can control the phase and amplitude of the transmitted, reflected, and scattered waves, show promise for breaking thermal radiation characteristics (to exceed the Shockley-Queisser limit for energy conversion efficiency) and manipulating the thermal radiation. In addition, newly emerging epsilon-near-zero (ENZ) materials enable unique optical functions, such as perfect absorption/emissivity, redirection of optical emission, and abnormally high nonlinearity, showing significant potential as advanced materials for optical/thermal wave manipulation. However, in most previous reports, metasurface/ENZ-nanostructure-based thermal emission control remains static and the metasurface properties are fixed upon fabrication. In addition, realizing thermal meta-structures with high absorptivity/emissivity, thermal stability, high temperature operation, and selective spectral response remains a great challenge.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Nov 16, 2022
- Source ID
- FA23862114057
Entities
People
- Ho Wai Howard Lee
Organizations
- Air Force Office of Scientific Research
- United States Air Force
- University of California, Irvine