The Characteristics of Plasmonic Thermal Emitters with Top Metal Perforated by Hole Array Arranged in Rhombus Lattice and the Study of Narrow Bandwidth Cavity Thermal Emitters

In this first topic of this thesis, the extraordinary transmission characteristics of silicon substrates with a silver film on top perforated with hole array arranged in a rhombus lattice are investigated in theory and experiment. It is found that the transmissions of Ag/Si modes are approximately linearly dependent on the numbers of degenerated modes in the longer wavelength range where the couplings between Ag/Si and Ag/air modes are weak. In the shorter wavelength range where Ag/Si and Ag/air are coupled together, the transmission peaks of Ag/Si modes are unapparent due to modes coupling. For plasmonic thermal emitters (PTEs) with hole array arranged in rhombus lattice, the peak intensities follow the blackbody radiation curve multiplying transmission efficiency of the top metal film which is dependent on the numbers of degenerated modes. In the second topic of this thesis, the SiO2 thickness of PTEs is increased to the order of μm to investigate cavity modes in the reflection and emission spectra, it is found that cavity modes (CMs) would be scattered by the periodic hole array and result in many Bragg scattered CMs in the spectra. Cavity thermal emitters (CTEs) with randomly distributed hole array (RDHA) are proposed to eliminate Bragg scattered CMs and Ag/SiO2 SPPs modes to realize narrower-band mid-infrared thermal emitters with purer spectra. The influence of hole size to the CMs is also investigated, it is found that larger scattering of light through larger surface hole array would form the localized CMs (LCMs) and Fabry-Perot hole shape resonance (FP hole) modes. Although CTEs with RDHA can offer pure emission spectra if the hole size is small, their output intensities are very weak due to low density of total hole area. Novel CTEs with short period of hole array (SPHA) are proposed to overcome the intensity problem. High output intensity, pure emission spectra, high temperature operation, narrow full width half maximum of emission peaks and low non-ideal effect such as LCMs and FP-hole modes and could achieve simultaneously. The wavelengths of emission peaks are tunable by the thickness of the cavity.