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The photonic band-gap of the two kinds of 1D photonic crystal structure which is composed of the form of (AB)C(BA), one with a metamaterial defect layer (MDL) and the other one with a dielectric defect layer (DDL) are studied. Our results show that in both cases, where there is only one defect layer, m=1, no defect mode exists, but for two defect layers ( m=2) there is a single defect mode which is centered in the middle of the band-gap. The width of the defect mode in DDL is narrower than that in MDL. For a number of defects of more than two ( m>2) and even, in both of the MDL and DDL structures, there is only one defect mode. For m>2 and odd, the defect mode in the MDL vanishes, but for DDL there is two defect-mode symmetrically centered in the middle of the band-gap. The effects of the defect layers refractive index value, the periodicity number of the structures and the incident angle on the properties of the defect modes and the transmittance spectrum are discussed. [ABSTRACT FROM AUTHOR]

In this paper, the nonlinear responses and optical properties modification in SK3 glass sample are investigated. The nonlinear responses measurements were performed by using of nonlinear transmission monitoring of 200 fs at 800 nm laser pulses. The optical power limiting threshold of the sample is measured to be about 40 mJ/cm2. The decrease of transmitted intensity is about 63% compared to the theoretical linear transmission at 270 mJ/cm2 incident pulse energy. For prediction of the experimental nonlinear behavior results, a theoretical model based on three-photon absorption and absorption of free carriers is presented. By fitting of experimental data with theoretical model, three-photon absorption coefficient and free-carrier absorption cross-section are reported. The photo-induced optical properties modification of the SK3 sample is investigated also. The modifications that appear as darkening are observed below breakdown threshold intensity. To analyses of modified region sizes, the laser pulse energy accumulation model is applied. [ABSTRACT FROM AUTHOR]

Abstract: This is an erratum to the paper [K. Jamshidi-Ghaleh, N. Mansour, Opt. Commun. 234 (2004) 419], in which a new method for measuring the nonlinear refractive index of materials using the moiré deflectometry is reported. The paper was published with an error in Eq. (4) and it has propagated through the paper. [ABSTRACT FROM AUTHOR]

In the present study, the effects of the configuration buckling on dielectric function of silicene, germanene and stanene are investigated. The behavior of the optical absorption spectrum and the refractive index dispersion are studied using the density functional theory in terms of incident photon energy at different buckling heights. The results show that for a fixed bond length, increasing the unit cell buckling height, increases the absorption and the refractive index in silicene and germanene but decreases in stanene. In addition, the absorption peaks shift toward the longer wavelengths (red shift) in the case of silicene and germanene by increasing the buckling height. For clear understanding of the mentioned results, the behavior of the optical absorption spectrum and refractive index dispersion at different buckling heights are studied within the present work. In the case of the silicene and germanene reduction of the band gap with increasing the buckling height could be regarded as the origin of this red shift. Meanwhile unlike the silicene and germanene, band-structure reshaping in stanene could explain the stanene blue shift as a result of the buckling height increment. [ABSTRACT FROM AUTHOR]