Optical properties of metallic glasses

Optical reflection spectra of metallic glasses (Pd₈₁Si₁₉ and Pd₈₄Si₁₆) were measured in the spectral range 0.03 to 12 eV and the optical constants were determined by Kramers-Kronig analysis. The experimental reflectivity spectra of glassy Pd₁₈Si₁₉ are similar to the one obtained for Au₈₁Si₁₉ prepared by getter sputtering in argon. However, the energy ranges where intra- and interband optical transitions occur are quite different for the two alloys.     

Optical properties of metallic nanowires

The optical response of metallic nanowires is determined taking into account the non-local electron response by use of a self-consistent method and a jellium model. An exact formula for the reflection factor is obtained in the usual case of an hydrodynamic dielectric function. Up to a constant factor it coincides with the non-retarded limit of the amplitude obtained in a previous calculation, leading finally to the same extinction function. This function is calculated for certain metallic nanowires of experimental interest (Na, Ag). From the non-retarded near field response, the scattering amplitude at any distance can be derived.     

Reflection properties of metallic photonic crystals

Received: 10 November 1997/Accepted: 16 November 1997     

一维金属光栅的透射光学特性

利用时域有限差分法模拟了一维金属光栅的透射光场的分布及光栅厚度等因素对透射光谱的影响.结果表明:特定波长的光通过金属光栅中的亚波长狭缝时有异常大的透过率增强.分析其物理起源,认为是类FabryPerot(FP)腔作用的结果.基底介电常量对类FP腔长度的调制导致了对透射光谱的影响.金属光栅表面激发的表面等离子体激元波与多缝干涉一样,对透射光谱有一定的影响,但不是形成增强的原因 关键词： 金属光栅 透射光学特性     

Electron-optical phase shift of magnetic nanoparticles I. Basic concepts

The electron-optical phase shift induced in the electron beam due to the interaction with the electromagnetic field of magnetized nanoparticles of defined shape and arbitrary dimensions is calculated, presented and discussed. Together with the computable knowledge of vector potential and magnetic induction, including the demagnetizing field, and with the extension to more realistic geometries which will be presented in part II, this theoretical framework can be employed for the interpretation of transmission electron microscopy experiments on magnetic particles on the nanometre scale.     

Analysis of phase shift of surface plasmon polaritons at metallic subwavelength hole arrays

We present the transmission spectra of light transmitting a metallic thin film perforated with differently shaped sub- wavelength hole arrays, which are calculated by a plane-wave-based transfer matrix method. We analyze the transmission peak positions and the phase-shift angles of different surface plasmon polariton （SPP） modes by using the microscopic theoretical model proposed by Haitao Liu and Philippe Lalanne [Liu Haitao, and Lalanne Philippe 2008 Nature 452 728], in which the phase shift properties of the SPPs scattered by the subwavelength hole arrays are considered. The results show that the transmission peak position and the minus phase shift angle of the SPP increase as the hole size increases. On the other hand, the effective dielectric constant of the metallic film can be deduced by the microscopic theoretical model.     

Optical properties of F centers in KCN crystal

Absorption, excitation and emission spectra of F centers in KCN were measured between 4.5 K and 175 K. Due to the cubic to orthorhombic structural phase transition at 168 K, the F band splits into three components. Their properties in the antiferroelectric phase (T < 83 K) are explained by an internal Stark effect due to the local electric field. The single emission band has a decay time of 21.5 nsec at 4.5 K.     

Optical phase shift analysis of n + 32S

A theory of optical phase shifts (OPS) developed for analyzing low-energy resonant cross sections is applied to analyze the total cross section for low-energy neutrons on n + ³²S. Phase shifts of a model for the optical potential are calculated at complex energies and compared with the OPS in order to determine the depth of its real and absorptive potentials.     

Optical properties of metallic nanoshell composites: The effects of temperature and particle clustering

The optical properties of a metallic nanoshell composite are studied theoretically using different effective medium theories with particular focus on the effects of variation in temperature and particle clustering on these properties. One unique result from our modeling is the persistent manifestation of the single-particle resonances of the individual nanoshells which cannot be found in a composite of solid particles. In addition, we observe red-shifts in the composite plasmon modes, as well as damping in the dielectric function spectrum as the temperature increases. Furthermore, a much greater red-shift will occur when these nanoshells coalesce to form fractal clusters in the composite, with the value of this shift increasing with decrease in the fractal dimension or increase in the cluster size. We further calculate the transmission at normal incidence through such composite thin films as a demonstration of how these effects can be observed experimentally.     

Optical and thermal properties of F and F aggregate centers in KF

A detailed investigation has been carried out of the optical and thermal properties of centers such as F, F_A, M and M_A in pure, Na-doped and Li-doped KF. Most centers exhibit properties which are qualitatively similar to those produced in other potassium halides with the notable exception of the F_A (Na) center, which has both Type I and Type II behavior.     

Optical nutation and photon echo by phase or amplitude shift of light waves

Optical nutation and photon echo caused by phase shift of a light wave incident on a resonant medium are considered. The case of simultaneous ultrashort perturbation of phase and amplitude is also treated. It is shown that a change of linear to circular polarization of incident light waves gives rise to an increase of the period and the decay time of optical nutation on the resonant atomic transitions J→J. On the contrary, the above mentioned period and decay time in the same situation are decreased on the resonant atomic transitions with the moment change J?J+1. This law in optical nutation can be taken as a base of the method for experimental identification of the atomic and molecular transitions. Moreover, the comparison of the theoretical and experimental optical nutation curves allows the probability of spontaneous emission to be determined.     

Optical properties of V6O13 single crystals in the metallic and the semiconducting phase

The optical reflection of V₆O₁₃ single crystals has been studied between 0.06 and 3 eV at temperatures both below and above the semiconductor-to-metal transition temperature (T_t?150K). In addition to the metallic reflection, present only at T>T_t, discrete resonances are observed in both phases: four with polarization E//b and three with E⊥b.The results of a dispersion analysis using classical-oscillator and Drude terms are presented. The resonances above 2 eV are attributed to oxygen 2p - vanadium 3d interband transitions. The maxima at the lower energies are interpreted as transitions between vanadium 3d subbands.     

R.F. Phenomena in nuclear gamma-resonance: Temporal Mössbauer spectroscopy,quasienergies and R.F. Collapse

The successful investigations of r.f. effects in NGR were recently in progress [1–3]. The purpose of this paper is to pay attention to some new theoretical results in this field which may be an object of the experimental realization.     

Optical measurements of ground-state properties of short-lived nuclei in resonance cells

Hyperfine structure and isotope shift of radioactive Hg, Au and Cd isotopes have been determined by optical spectroscopy. In all cases the atoms were confined in a resonance cell. The various variants of the cell technique and alternative methods as the resonance ionization spectroscopy related to the investigation of short-lived nuclei are described, and some results are discussed.