Transmission properties of a single metallic slit: From the subwavelength regime to the geometrical-optics limit

In this work we explore the transmission properties of a single slit in a metallic screen. We analyze the dependence of these properties on both slit width and angle of incident radiation. We study in detail the crossover between the subwavelength regime and the geometrical-optics limit. In the subwavelength regime, resonant transmission linked to the excitation of waveguide resonances is analyzed. Linewidth of these resonances and their associated electric field intensities are controlled by just the width of the slit. More complex transmission spectra appear when the wavelength of light is comparable to the slit width. Rapid oscillations associated to the emergence of different propagating modes inside the slit are the main features appearing in this regime.Comment: Accepted for publication in Phys. Rev.

Quantum Dynamics in Non-equilibrium Strongly Correlated Environments

We consider a quantum point contact between two Luttinger liquids coupled to a mechanical system (oscillator). For non-vanishing bias, we find an effective oscillator temperature that depends on the Luttinger parameter. A generalized fluctuation-dissipation relation connects the decoherence and dissipation of the oscillator to the current-voltage characteristics of the device. Via a spectral representation, this result is generalized to arbitrary leads in a weak tunneling regime.Comment: 4 pages, 1 figur

Single- and multi-walled carbon nanotubes viewed as elastic tubes with Young's moduli dependent on layer number

The complete energy expression of a deformed single-walled carbon nanotube (SWNT) is derived in the continuum limit from the local density approximation model proposed by Lenosky {\it et al.} \lbrack Nature (London) {\bf 355}, 333 (1992)\rbrack and shows to be content with the classic shell theory by which the Young's modulus, the Poisson ratio and the effective wall thickness of SWNTs are obtained as $Y=4.70$TPa, $\nu=0.34$, $h=0.75{\rm \AA}$, respectively. The elasticity of a multi-walled carbon nanotube (MWNT) is investigated as the combination of the above SWNTs of layer distance $d=3.4 {\rm \AA}$ and the Young's modulus of the MWNT is found to be an apparent function of the number of layers, $N$, varying from 4.70TPa to 1.04TPa for N=1 to $\infty$.Comment: 4 pages, 1 figur

INTERFACE SPINODAL DECOMPOSITION IN LPE InxGa1-xAsyP1-y LATTICE MATCHED TO InP

Nous montrons en utilisant un MEBT en modes image et microanalyse X qu'un champ de déplacement quasipériodique et une modulation de composition associée existent dans des couches de InGaAsP épitaxiées sur substrat InP orienté (001). Nous vérifions que cette modulation n'est pas un artefact dû à des effets de canalisation. Le domaine de température et de composition pour lequel la structure quasipériodique est observée est en bon accord avec la prédiction théorique d'une zone d'instabilité spinodale dans la phase solide.We show by STEM imaging and X-ray microanalysis that a quasiperiodic strain field and an associated composition modulation exist in InGaAsP layers LPE-grown on (001) InP. This modulation is checked not to be an artefact due to channelling effects. The composition and temperature range for which the quasiperiodic structure is observed is in good agreement with the theoretical prediction of a spinodal instability zone in the solid phase