In this work we describe a dipole wave propagation through a two-dimensional nanoparticles array, where the array is doped with magnetic impurities randomly distributed. The effect of impurities is a trajectory resorting in the wave propagation; this phenomenon is described by means of the percolation theory.
In this work we describe a resonant interaction between nanoparticles considering the geometric parameters using
a multidisciplinary approach to mode coupling theory. The study groups are differentiable equations describing
the resonant processes.
In this work, we describe the behavior of the electromagnetic field on a Nanostructured interface using the
coupled mode theory. The study is performed by associating time-dependent parameters to a set of polarized
particles randomly distributed on an dielectric substrate. As a result, we obtain the conditions to generate a
negative refractive index as a function of the distance between two particles in harmonic oscillation, in this way
we show the possibility to synthetize Metamaterials from the nanoparticles arrays.
We describe the mode solutions for the Helmholtz Equation using the operator formalism. The study is extended
to the structural solution for the focused non-linear Schrödinger equation (NLSE). With this treatment, we obtain
for the NLSE a reduced partial differential equation, whose characteristic solution has an eikonal structure
which allows us a geometrical analysis. Focusing region in non-linear media is described by means of an envelope
region of eikonal trajectories establishing similar behaviors with caustic structures. In particular, if the boundary
condition consists of a slit shape curve, the focusing profile corresponds with the evolute of the curve. In general,
the profile satisfies a non-linear partial differential equation whose structure remains non-variable under changes
of variables which may represents scaling or rotations. This feature permits us to extend the analysis to other
kind of focusing regions, such as focusing vortex.
The use of an optical fiber as a distributed sensor for detecting and locating intruders over long perimeters (>10 km) is described. Phase changes resulting from either the pressure of the intruder on the ground immediately above the buried fiber or from seismic disturbances in the vicinity are sensed by a phase-sensitive optical time-domain reflectometer (Φ-OTDR). Light pulses from a cw laser operating in a single longitudinal mode and with low (MHz/min range) frequency drift are injected into one end of the single mode fiber, and the backscattered light is monitored with a photodetector. In laboratory tests with 12 km of fiber on reels, the effects of localized phase perturbations induced by a piezoelectric fiber stretcher on Φ-OTDR traces were characterized. In field tests in which the sensing element is a single mode fiber in a 3-mm diameter cable buried in a 20-46 cm deep, 10 cm wide trench in clay soil, detection of intruders on foot up to 4.6 m from the cable line was achieved. In desert terrain field tests in which the sensing fiber is in a 4.5-mm diameter cable buried in a 30 cm deep, 75 cm wide trench filled with loose sand, high sensitivity and consistent detection of intruders on foot and of vehicles traveling down a road near the cable line was realized over a cable length of 8.5 km and a total fiber path of 19 km. Based on these results, this technology may be regarded as a candidate for providing low-cost perimeter security for nuclear power plants, electrical power distribution centers, storage facilities for fuel and volatile chemicals, communication hubs, airports, government offices, military bases, embassies, and national borders.
The use of an optical fiber as a distributed sensor for detecting, locating, and (with suitable signal processing) classifying intruders is proposed. Phase changes resulting from either the pressure of the intruder on the ground immediately above the buried fiber or from seismic disturbances in the vicinity are sensed by a phase-sensitive optical time-domain reflectometer (Φ-OTDR). Light pulses from a cw laser with a narrow (kHz range) instantaneous linewidth and low (MHz/min range) frequency drift are injected into one end of the single mode fiber, and the backscattered light is monitored with a photodetector. Results of analyses and experimental studies to establish the feasibility of the concept are described. Simulations predict a range of 10 km with 35 m range resolution and 30 km with 90 m range resolution. Experiments indicate adequate (several π-rad) phase changes are produced by intruders on foot for burial depths in the 20 - 40 cm range in sand and in clay soils. A phase perturbation in a fiber has been detected and located in a laboratory demonstration of the Phi-OTDR using an Er:fiber laser as the light source. This technology could in a cost-effective manner provide enhanced perimeter security for nuclear power plants, electrical power distribution centers, storage facilities for fuel and volatile chemicals, communication hubs, airports, government offices, military bases, embassies, and national borders.