The Properties And Applications Of Optical Tamm States In Metal-Distributed Bragg Reflectors

Tamm states are a kind of surface states of localized electronics in solid-state physics. Tamm predicted the existence of Tamm states at the edge of a truncated periodic atomic potential in the 1930s, and Tamm states were first observed in semiconductor superlattices in 1990. Optical Tamm states (OTSs) were first named by A. V. Kavokin et. al.[A. V. Kavokin, I. A. Shelykh, and G. Malpuech, Phys. Rev. B,72,233102(2005).] in 2005. OTSs, in analogy with Tamm surface states, are a kind of interface modes. The enhanced field associated with OTSs is localized at the interface between two different media. The existence of OTSs has been widely demonstrated in one-dimensional photonic crystal heterostructures and metal-distributed Bragg reflectors (DBR). Compared with the traditional surface states, OTSs can be directly excited in both the TE and TM polarizations, even at normal incidence. OTSs are usually associated with a sharp reflection dip (or a sharp transmission peak) in the photonic bandgap (PBG) region, and the value of the full width at half maximum of the reflection dip is small. These characters of OTS can be used to the design of resonant optical filters and high sensitive sensors. Moreover, the potential (or practical) applications of OTSs have been proposed (or explored), in such uses as polariton lasers (with or without cavity), optical switches, one-way propagation, enhancement of Faraday rotation, and enhancement of Kerr effects. Because of the special properties and potential applications of OTSs, much attention has been drawn to them in recent years.The reflectivity maps are readily obtained by applying the transfer matrix method in multilayer structures. Based on the reflectivity maps, the existence of multiple OTSs are demonstrated at the metal-DBR interface; the mode splitting phenomena, wich result from the coupling between two OTSs, are investigated in DBR-metal-DBR structure; the strong interactions of OTSs and excitons from quantum well are depicted in metal-DBR structure containing a single quantum well. The main works involved in this dissertation are as follows:Firstly, we investigate the reflectivity map in metal-DBR structure at normal incidence. The existence of multiple OTSs is demonstrated in this structure. It is found that an OTS is periodic occurrence with the variation of the thickness of the top layer, which is adjacent the metal film, for a given wavelength. The eigenenergy for the corresponding OTS mainly depends on the thickness of the top layer. The appropriate thicknesses of metal film are proposed for the convenient observation of OTSs. This result may be useful in designing a new type of multichannel filter in optical communication systems.Secondly, the coupling between two OTSs with the same eigenenergy is numerically investigated in DBR-metal-DBR structure. The reflectivity map in this structure at normal incidence is obtained. Two splitting branches appear in the PBG region, when both adjacent dielectric layers of the metal film are properly set. And the splitting energy of two branches strongly depends on the thickness of metal film. According to the electric field distribution in this structure, it is found that the high-energy branch corresponds to the antisymmetric coupling between two OTSs, while the low-energy branch is associated with the symmetric coupling between two OTSs. Moreover, the optical difference frequency of two branches is located in a broad terahertz region.Thirdly, the interactions of OTSs and excitons from quantum well are investigated in metal-DBR structure. When the eigenfrequency of OTS is close to the frequency of excitons, two splitting branches, i.e., the high-energy branch (HEB) and the low-energy branch (LEB) of Tamm plasmon polaritons (TPP) resulting the coupling between OTSs and excitons, appear in the reflectivity map. HEB and LEB of TPP exhibit characteristic anticrossing behaviour. Rabi spiltting energy is periodic oscillation with the variations of the position of the quantum well in the top layer. When the quantum well locates in the antinode of the electric field, Rabi spiltting energy achieves the maximum value; while the quantum well locates in the node of the electric field, the Rabi spiltting phenomena disappear because the excitons in quantum well cannot be effectily excited. Under oblique incidence, the frequency of excitons is blueshifted at the vicinity of resonance.