SUMMARY
Tailoring the spectral and directional radiative properties of engineered micro/nanostructures has enormous applications in photonics, microelectronics, and energy conversion systems. This thesis aims at (1) design and analysis of micro/nanostructures based on magnetic resonance and wave interference effects to achieve tunable coherent thermal emission or enhanced optical transmission; (2) microfabrication of the designed structures; and (3) measurement of the radiative properties of the fabricated samples using spectrometric techniques at temperatures from 300 K to 800 K. Magnetic polaritons have been recognized as a mechanism to achieve extraordinary optical transmission/absorption, through the comparison between an equivalent LC circuit model and the rigorous coupled-wave analysis (RCWA). With carefully tuned geometric parameters, the resonant frequencies can be favorably tailored for specific applications. A coherent emission source can be realized with deep gratings by excitation of magnetic polaritons and has been explained through the LC circuit model. Different from the surface plasmon/phonon polaritons, the magnetic polaritons are insensitive to the directions, and associated electromagnetic field is strongly localized. A test structure will be fabricated using a metallic slit array and a thin film separated by a spacer, and tested for coherent thermal emission. An asymmetric Fabry-Perot resonant cavity was studied as a potential coherent emission source based on the wave interference effect. The reflectance is measured at room temperature using a Fourier transform infrared spectrometer, and the emittance can be indirectly obtained from Kirchhoff’s law. A high-temperature emissometer was built to measure the thermal emission of fabricated samples at elevated temperatures. Cautions need to be taken for layered structures with nonuniform temperature distributions, and a generalized Kirchhoff’s law was deduced from the direct and indirect approaches. The results obtained from this thesis will facilitate the design and application of nanostructures in energy-harvesting systems.