SUMMARY

The objective of this thesis is to identify, design, and experimentally demonstrate unique structures with coherent emission characteristics, which are manifested by a sharp spectral peak and a narrow angular lobe in a well-defined direction. The present study proposes a novel structure made of a one-dimensional (1D) photonic crystal (PC) and a polar material or a metal as a coherent thermal emission source. A salient feature of photonic crystals is the existence of photonic band structures. It has been shown that 1D PCs can support a surface mode or surface wave in the stop band. When the thicknesses and dielectric properties of the PC are adjusted, surface waves can be excited at the interface between the PC and a polar material by radiative waves propagating in air, for either polarization. The conditions that cause a large emission in a narrow spectral range and an angular lobe in a well-defined direction are thoroughly investigated. Based on the modeling results, the coherent emission source is optimally designed for the near-infrared spectral region and fabricated using thin-film deposition techniques. The spectral reflectance of fabricated sample is measured at near normal incidence with a Fourier transform infrared spectrometer, and measured reflectance is compared with theoretical prediction. This is the first experimental demonstration of gratingless coherent thermal emission source by exciting surface waves without employing a prism. In addition to the large enhancement in the far-field emissivity with the use of the coherent emission source, for applications in the energy conversion devices, the energy transfer can be greatly enhanced by placing the source close to the detector, via photon tunneling of evanescent waves. The energy streamline method based on the Poynting vector of the coupled forward and backward waves is used to study photon tunneling phenomenon associated with the lateral shift of energy path.