This dissertation describes a theoretical and experimental study on coherent thermal emission from thin-film multilayer structures. A novel multilayer structure consisting of a one-dimensional photonic crystal and a polar material (or a metal) is proposed as a coherent thermal-emission source. Surface electromagnetic waves can be excited at the edge of photonic crystal, enabling coherent emission characteristics (i.e., spectral- and directional-selectivity in the emissivity). A near-infrared coherent emission source is designed and fabricated using vacuum deposition and chemical vapor deposition techniques. Measurements were performed using a Fourier-transform infrared spectrometer and a laser scatterometer. The agreement between the resonance conditions obtained from experiments and the calculated dispersion relation confirms that surface waves at the photonic crystal-metal interface can be utilized to build coherent thermal-emission sources. The second part of this dissertation focuses on the energy propagation direction in near-field thermal radiation. The energy streamline method based on the Poynting vector is applied to near-field thermal radiation by incorporating the fluctuational electrodynamics, in which thermal emission is viewed as originated from random motion of electric dipoles at temperatures above absolute zero. It is shown that the Poynting vector is decoupled for each parallel wavevector component due to the randomness of thermal emission. The spectral radiative energy travels in infinite directions along curved lines; this is a fundamental characteristic of near-field thermal radiation. The findings in this dissertation are important for the design of near-field optical sensors and energy conversion devices.

<p>U radu je pokazano da frekvencijski zavisna impedansa<br />zemlje kao povratnog provodnika, pri proizvoljnoj<br />učestanosti može veoma tačno da se odredi pomoću<br />fluksa kompleksnog Pointingovog vektora. Za<br />izračunavanje kompleksnog Pointingovog vektora,<br />neophodno je prethodno odrediti raspodelu struje u<br />zemlji, kao i raspodelu magnetskog polja i u zemlji i u<br />vazduhu iznad povr&scaron;i zemlje. Obe ove raspodele takođe<br />su značajne za analizu elektroenergetskih sistema.</p> / <p>The thesis shows that the Earth return impedance at<br />arbitrary low frequency can be accurately determined<br />from the complex Poynting vector flux. For the complex<br />Poynting vector calculation, first it is necessary to<br />determine the current distribution inside the ground, as<br />well as the magnetic field distribution both inside the<br />ground and in the air above the ground surface. Both<br />distributions are also significant for power electrical<br />systems analysis.</p>