We predict solitonlike pulses and precursors at the Stokes frequency in stimulated electronic Raman scattering at the photoionization front of pumping x-ray radiation. We find two different solitonlike patterns that d...
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We predict solitonlike pulses and precursors at the Stokes frequency in stimulated electronic Raman scattering at the photoionization front of pumping x-ray radiation. We find two different solitonlike patterns that depend on different photoionization mechanisms.
We found conditions for excitation of bright-bright 2pi solitons in stimulated Raman scattering that involves nutation of population at Raman quantum levels, for two (laser- Stokes) and three (e.g., laser - Stokes - a...
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We found conditions for excitation of bright-bright 2pi solitons in stimulated Raman scattering that involves nutation of population at Raman quantum levels, for two (laser- Stokes) and three (e.g., laser - Stokes - anti-Stokes) components. The soliton components at all participating frequencies are bright solitons of the same, Lorentzian, shape, in contrast to the well-known bright - dark soliton combination in stimulated Raman scattering.
Eigenmodes of three-wave interactions in second-order [chi(2)] nonlinear materials are explored that have a no-energy-exchange property between all the waves. They are shown to exhibit cross-induced nonlinear refracti...
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Eigenmodes of three-wave interactions in second-order [chi(2)] nonlinear materials are explored that have a no-energy-exchange property between all the waves. They are shown to exhibit cross-induced nonlinear refraction and to be ideal candidates for amplitude-dependent phase control in chi(2) materials that emulate nonlinear refractive-index effects in third-order [chi(3)] materials. It is shown that all these eigenmodes are spatially stable.
We describe a system that communicates motion information computed in a 2D photosensitive array using fully arbitered, asynchronous channels. The architecture is neurally inspired, and employs analog winner-takes-all ...
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We describe a system that communicates motion information computed in a 2D photosensitive array using fully arbitered, asynchronous channels. The architecture is neurally inspired, and employs analog winner-takes-all (WTA) circuits, instead of the digital binary-tree arbiters found in other designs. We have fabricated a prototype system that incorporates an array of 9 x 12 pixels in a 2 mu m, double-polysilicon, double-metal process. Experimental results verify system functionality with a full-handshaking communication cycle of 3 mu s. We have tested the WTA circuits independently, and have verified their operation down to an 18 ns cycle.
Deep-learning-based semi-supervised learning (SSL) methods have achieved a strong performance in medical image segmentation, which can alleviate doctors' expensive annotation by utilizing a large amount of unlabel...
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Astronomical observations near the horizon have historically been made for naval navigation and for determining the time of sunset. Recent applications include near-horizon daytime scene simulation to support infrared...
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Astronomical observations near the horizon have historically been made for naval navigation and for determining the time of sunset. Recent applications include near-horizon daytime scene simulation to support infrared search and track and infrared seeker studies, The ray path of the setting or rising Sun can be highly distorted near the horizon, and it is seldom rectilinear. An accurate model of atmospheric refraction must include the observer's altitude as well as range, frequency, and atmospheric pressure and temperature. At infrared through ultraviolet frequencies, refractivity depends strongly on the vertical temperature profile, and an explicit relationship between refractivity and temperature can be obtained. This article describes a refraction model we developed that closely reproduces the profile of the setting Sun.
An analysis of Monte Carlo algorithms for the simulation of Gibbs random field images is presented, which addresses various theoretical and computational issues about their algorithmic behavior. The concept of relativ...
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An analysis of Monte Carlo algorithms for the simulation of Gibbs random field images is presented, which addresses various theoretical and computational issues about their algorithmic behavior. The concept of relative entropy is introduced as the primary analytical tool, and convergence of the simulation algorithms is discussed in terms of the relative entropy. This approach allows us to view the simulation of Gibbs random field images as a constrained, convex optimization problem and it results in a systematic study of various Monte Carlo simulation algorithms under a common analytical framework. The problems of proper initialization, of maximizing the rate of convergence at each iteration, and of minimizing the rejection rate are discussed. A computational comparison of various Monte Carlo simulation algorithms is also presented.
Neuromorphs or artificial neural microcircuits imitates the algorithmic behavior of the biological systems being inspired by the function, structure, and plasticity of the biological nervous systems. The elements of a...
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Neuromorphs or artificial neural microcircuits imitates the algorithmic behavior of the biological systems being inspired by the function, structure, and plasticity of the biological nervous systems. The elements of adaptation, learning and memory are employed within each processing stage of these systems. Neuromorphic engineers make use of the similarities between the human neuron and transistors to utilize the physics of CMOS (complementary metal oxide semiconductor) technology for implementation of the physical process that underline neural computation. Engineers are shifting to a new paradigm called organizing principles because of the fundamental limitations on the ways systems are designed. The specialties in neuromorphic system development includes locomotion control, auditory, vision and so on. The system finds its application in neuro-grid computing based on computer infrastructures similar to those of the brain's cortical neurons, biocompatible retinas and cochleas.
In this paper we present a definition for the entropy for time-varying continuous-time systems. This entropy differs significantly from the entropy for discrete-time systems, which is defined as the memoryless compone...
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In this paper we present a definition for the entropy for time-varying continuous-time systems. This entropy differs significantly from the entropy for discrete-time systems, which is defined as the memoryless component of the spectral factor of an operator related to the system. Properties of this entropy are discussed, the relationships with H-2 and H-infinity, as well as the relationship with the discrete-time entropy.
The feasibility of optically pumped infrared laser based on the intersubband transitions in multiple quantum wells is studied theoretically. The criteria for the population inversion and efficient lasing operations ar...
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The feasibility of optically pumped infrared laser based on the intersubband transitions in multiple quantum wells is studied theoretically. The criteria for the population inversion and efficient lasing operations are established. The system consisting of the superlattice with four quantum wells per period is proposed and shown to satisfy the above criteria. The relaxation processes are investigated with electron-phonon interaction being given a rigorous theoretical treatment. It is shown that in the proposed structure, optical gain in excess of 300 cm-1 can be realized under practical pumping conditions. Modification and optimization of the proposed laser are discussed.
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