The properties of ultrashort gaussian pulse propagation in a dispersive, attenuative medium are reviewed with emphasis on the pulse velocity. Of particular interest is the group velocity whose physical interpretation loses meaning in causally dispersive materials as the temporal pulse width decreases into the ultrashort pulse regime. A generalized definition of the group velocity that applies t...

Evolution of the main signal in a Lorentz dispersive medium is considered. The signal propagating in the medium is excited by a sine-modulated pulse signal, with its envelope described by a hyperbolic tangent function. Both uniform and non-uniform asymptotic representations for the signal are found. It is shown when the uniform representation can be reduced to the non-uniform one. The results o...

We present a method to measure the spectrally-resolved transmission matrix of a multiply scattering medium, thus allowing for the deterministic spatiospectral control of a broadband light source by means of wavefront shaping. As a demonstration, we show how the medium can be used to selectively focus one or many spectral components of a femtosecond pulse, and how it can be turned into a control...

Finite-difference time-domain (FDTD) simulations of any electromagnetic problem require truncation of an often-unbounded physical region by an electromagnetically bounded region by deploying an artificial construct known as the perfectly matched layer (PML). As it is not possible to construct a universal PML that is non-reflective for different materials, PMLs that are tailored to a specific pr...

A complex quantitative model for nearly constant loss ~NCL! is proposed based on an effective-medium approach. Unlike previous NCL response models, it satisfies the Kronig–Kramers transform relations. Here the effective-medium dielectric-level model depends directly on the concentration of mobile charge present and its complex dielectric response is identified as arising from electrical interac...

The propagation of low frequency or long wavelength disturbances in periodically layered media is considered. An asymptotic series is derived for the frequency of the first branch of the Bloch wave spectrum. The expansion is in dimensionless wavenumber and is developed explicitly for SH waves traveling obliquely through layerings with arbitrary periodic stratification. The first dispersive term...

The precipitation of carbonate minerals induced by halophilic bacteria has aroused wide concern. The study aimed to investigate the characterization and process of biomineralization in high salt systems by halophilic Chromohalobacter israelensis LD532 (GenBank: KX766026) bacteria, isolated from the Yinjiashan Saltern in China. Carbonate minerals were induced in magnesium sulfate and magnesium c...

We want to study thermal corrections on the speed of light at low temperature considering temperature dependence of photon vacuum polarization tensor at two-loop level in the standard QED‎. It is found that the heat bath behaves as a dispersive medium for the propagation of light and reduces its speed proportional to the second order of temperature‎. ‎Similarities and differences‎, ‎in light ...