P. Chamorro-Posada

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Giant Goos-Hänchen shifts and radiation-induced trapping are studied at the planar boundary separating two focusing Kerr media within the framework of the Helmholtz theory. The analysis, valid for all angles of incidence, reveals that interfaces exhibiting linear external refraction can also accommodate both phenomena. Numerical evidence of these effects is(More)
The refraction of dark solitons at a planar boundary separating two defocusing Kerr media is simulated and analyzed, for the first time (to our knowledge). Analysis is based on the nonlinear Helmholtz equation and is thus valid for any angle of incidence. A new law, governing refraction of black solitons, is combined with one describing bright soliton(More)
A general dark-soliton solution of the Helmholtz equation (with defocusing Kerr nonlinearity) that has on- and off-axis, gray and black, paraxial and Helmholtz solitons as particular solutions, is reported. Modifications to soliton transverse velocity, width, phase period, and existence conditions are derived and explained in geometrical terms. Simulations(More)
A different spatial soliton-bearing wave equation is introduced, the Helmholtz-Manakov (HM) equation, for describing the evolution of broad multicomponent self-trapped beams in Kerr-type media. By omitting the slowly varying envelope approximation, the HM equation can describe accurately vector solitons propagating and interacting at arbitrarily large(More)
A generic nonparaxial model for pulse envelopes is presented. Classic Schrödinger-type descriptions of wave propagation have their origins in slowly-varying envelopes combined with a Galilean boost to the local time frame. By abandoning these two simplifications, a picture of pulse evolution emerges in which frame-of-reference considerations and space-time(More)
Semi-empirical quantum chemistry methods offer a very interesting compromise between accuracy and computational load. In order to assess the performance of NDDO methods in the interpretation of terahertz spectra, the low frequency vibration modes of three crystalline materials, namely, polyethylene, poly(vinylidene fluoride) form II and α-D-glucose have(More)
The fractal structure of real world objects is often analyzed using digital images. In this context, the compression fractal dimension is put forward. It provides a simple method for the direct estimation of the dimension of fractals stored as digital image files. The computational scheme can be implemented using readily available free software. Its(More)
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