Researches On Photon Transmission In Low-Dimensional Nanostructures

In recent years, the properties of light propagation in low dimensional quantum structures such as superlattices (SL's) have attracted much attention theoretically and experimentally. In this thesis, we present some detailed theoretical investigations on localized plasmon modes and light transmission properties in SL's with structural defects.Applying the Maxwell equations in a combination with the Bloch theorem, we study the properties of the localized plasmon modes in a semi-infinite semiconductor SL with cap layer. The results show that in such a structure there exist three localized plasmon modes. They may appear either in the gap between two bulk plasmon bands, or below and above the bulk plasmon bands. The evolution from the extended plasmon modes to the localized plasmon modes can clearly be tracked with the change of the structural parameters or the relative electron density. A brief analysis of these results is given. When the cap layer is the left-handed materials, we found that more modes appear or disappear. It is suggested that the localized plasmon modes can be artificially controlled by adjusting the parameters of the cap layer.We investigate the behavior of light propagation in a periodic superlattice containing a Thue-Morse defect. A comparison is made when the Thue-Morse structure is composed of the right-handed materials, and is composed of the right-handed materials and the left-handed materials. The effects of Thue-Morse structure and incident angle on the optical transmission spectra in these structures have been discussed by the transfer matrix method. The results that, the band gap is increased while the incident angle or the numbers of Thue-Morse structure is increased. When the Thue-Morse structure is composed of the right-handed materials and the left-handed materials, the band gap becomes wider. This will be very useful for the design of quantum devices.