Plasmon-induced terahertz absorption and photoconductivity in a grid-gated double-quantum-well structure

The terahertz absorption spectra of plasmon modes in a grid-gated double-quantum-well field-effect transistor structure is analyzed theoretically and numerically using the scattering matrix approach and is shown to faithfully reproduce strong resonant features of recent experimental observations of terahertz photo-conductivity in such a structure.     

The effects of sample preparation methods on the variability of the electrospray ionization response for model drug compounds

A post-column infusion system was developed in order to analyze suppression of electrospray ionization (ESI) tandem mass spectrometry response in the presence of endogenous plasma interferences. By enabling direct detection of these interfering components, this experimental system was used to analyze the ability of several common extraction procedures to remove endogenous plasma components that cause changes in the ESI response of model drug substances. Methyl-t-butyl ether (MTBE) liquid-liquid, Oasis and Empore solid-phase, and acetonitrile (ACN) protein precipitation sample preparation methods were tested using the post-column infusion system. In all cases, ACN protein precipitation samples showed the greatest amount of ESI response suppression while liquid-liquid extracts demonstrated the least. In addition, the three test compounds, phenacetin, caffeine, and a representative Merck compound, demonstrated that ESI response suppression is compound dependent. Suppression was greatest with caffeine, the most polar analyte, and the smallest for the Merck compound, the least polar analyte. Copyright 1999 John Wiley & Sons, Ltd.     

Terahertz excitation of the higher-order plasmon modes in field-effect transistor arrays with common and separate two-dimensional electron channels

Using a rigorous electrodynamic approach, the spectra of the terahertz response of periodically ordered arrays of field-effect transistors with two-dimensional electron channel were calculated. It was shown that the higher-order plasmon resonances can be excited in such structures at frequencies above 10 THz.     

Spectrum of polariton excitations of a two-dimensional electron plasma in a magnetic field

Polariton excitations associated with magnetoplasma and cyclotron oscillations in a two-dimensional (2D) electron plasma are studied. In contrast to previous works by other authors, it is concluded that there exists a low-frequency nontransmission band in the spectrum of 2D surface magnetoplasma polaritons. Radiative polariton excitations associated with nonuniform cyclotron oscillations of electrons in a 2D system are investigated. Pis’ma Zh. éksp. Teor. Fiz. 68, No. 3, 200–204 (10 August 1998)     

Total light absorption in plasmon resonance nanostructures

The effect of total light absorption in metal nanostructures of different type is described within the model of an equivalent oscillating electrical circuit. The condition for total light absorption is found, which, independent of the nanostructure type, is reduced to the condition of optical impedance matching on the nanostructure surface at the plasmon resonance frequency.     

Total resonant absorption of light by plasmons on the nanoporous surface of a metal

We have calculated light absorption spectra of planar metal surfaces with a two-dimensional lattice of spherical nanovoids just beneath the surface. It is shown that nearly total absorption of light occurs at the plasma resonance in a void lattice in the visible range when the intervoid spacing and the void deepening into the metal are thinner than the skin depth, which ensures optimal coupling of void plasmons to external light. We conclude that the absorption and local-field properties of this type of nanoporous metal surface can be effectively tuned through nanoengineering of the spherical pores and that they constitute a very attractive system for various applications in future submicron light technology.     

关于单位园周上阶梯函数的性质

Ｔ．Ｓｈｅｉｌ－Ｓｍａｌｌ［１］讨论了阶梯函数的Ｆｏｕｒｉｅｒ级数。本文对［１］中所涉及到一些阶梯函数的性质进行了详细讨论，并给出了详细证明。     

Superradiant optical emitters coupled to an array of nanosize metallic antennas

We study the properties of an array of Au ring nanoantennas fed by an ensemble of coherent emitters. The luminescence of the emitters is strongly enhanced at certain wavelengths due to the excitation of two types of resonances-the diffractive Rayleigh anomalies associated with the opening of new diffraction orders and the localized surface plasmons of the nanoantennas. We show that the two families of resonances can spectrally overlap and lead to anticrossings or cumulative enhancements depending on the symmetries of the modes. This rich optical behavior induces marked changes in the linewidth, shape, and amplitude of the peaks and could be potentially used to tune the luminescence of superradiant sources with new flexibility.     

极限方程有奇性的一类六阶椭圆型方程混合边值问题解的渐近式

该文研究极限方程在部分边界上为退缩椭圆型(椭圆-抛物)的一类六阶椭圆型方程混合边值问题的奇摄动,在适当的假设下,应用改进了的多重尺度法,求得其解包括边界层和套层在内除了半圆域的两个角点外,在整个半圆域中有任意阶的一致有效的渐近展开式.     

Photonic absorption bands in the spectra of nanoporous metallic films

The light absorption spectra of multilayer nanoporous metallic films containing spherical dielectric inclusions are calculated in the framework of the self-consistent electrodynamic approach (the Korringa-Kohn-Rostoker method). It is demonstrated that the coupling between Mie plasmons in different layers of nanopores leads to the formation of strong light absorption bands over a wide range of frequencies.