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Entangled State Creation by a Nonlinear Coupler Pumped in Two Modes

Duc V. E., Long V. C.

Computational Methods in Science and Technology

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2016

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Vol. 22, No. 4

245--252

EN

In this paper we consider a system with two nonlinear oscillators which are coupled via a nonlinear interaction. In order to excite the system, we use two external coherent fields. Two oscillators have different frequencies. It follows from numerical simulation that evolution of the system is similar to that of a combination of n-photon states. Therefore, the considered system behaves as so-called nonlinear quantum scissor. Nevertheless, evolution of the system generates Bell-like states in several times with very high probability. Because of the nonlinear properties of oscillators and their interaction, the system creates a truncation of optical states, which leads to obtain two-qubit states. It will also be shown that these states appear several times in the qutrit-qutrit system.

2

Electromagnetically induced transparency in systems with degenerate autoionizing levels in Λ-configuration

Dinh T. B., Leoński W., Perina J., Long V. C.

Optica Applicata

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2013

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Vol. 43, nr 3

471--484

EN

We discuss a Λ-like model of atomic levels involving two autoionizing (AI) states of the same energy. The system is irradiated by two external electromagnetic fields (strong – driving and weak – probing). For such a system containing degenerate AI levels we derive the analytical formula describing the medium susceptibility. We show that the presence of the second AI level leads to the additional electromagnetically induced transparency (EIT) window appearance. We show that the characteristics of this window can be manipulated by changes of the parameters describing the interactions of AI levels with other ones. This is a new mechanism which leads to additional transparency windows in EIT model, that differs from the mechanism where a bigger number of Zeeman sublevels is taken into account.

3

Propagation Technique for Ultrashort Pulses III: Pulse Splitting of Ultrashort Pulses in a Kerr Medium

Long V. C., Viet H. N., Trippenbach M., Xuan K. D.

Computational Methods in Science and Technology

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2008

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Vol. 14, nr 1

21-26

EN

Impact of such terms as third order dispersion, self-steepening and stimulated Raman scattering on evolution of ultrashort pulses is considered in detail. Under influence of these effects, pulse did not maintain its initial shape. Pulse splits into constituents, its spectrum also evolving into several bands which are known as optical shock and self-frequency shift phenomena. We concluded that when the input peak power is large enough, dynamics of pulse splitting will be complicated. Our numerical simulations were in good agreement with experimental results.

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Propagation Technique for Ultrashort Pulses. II: Numerical Methods to Solve the Pulse Propagation Equation

Long V. C., Viet H. N., Trippenbach M., Xuan K. D.

Computational Methods in Science and Technology

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2008

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Vol. 14, nr 1

14-19

EN

We presented the numerical technique to approximately solve the pulse propagation equation. Two efficient methods for this problem, the Split-Step Fourier and the fourth order Runge-Kutta methods are considered. Their high accuracy are shown by comparison with analytical solutions in some particular situations. Our numerical experiments are implemented for soliton propagation and interacting high order solitons. We also numerically investigate an important technique to create ultrashort pulses, which is known as the pulse compression. It is based on high order soliton propagation in Kerr media when the effect of stimulated Raman scattering is taken into account.

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Propagation Technique for Ultrashort Pulses. I: Propagation Equation for Ultrashort Pulses in a Kerr Medium

Long V. C., Viet H. N., Trippenbach M., Xuan K. D.

Computational Methods in Science and Technology

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2008

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Vol. 14, nr 1

5-11

EN

In this work we investigated propagation of ultrashort laser pulses in dispersive nonlinear media. We derived a general propagation equation of pulses which includes the linear and nonlinear effects to all orders. We studied in the specific case of Kerr media and obtained an ultrashort pulse propagation equation called a Generalized Nonlinear Schrödinger Equation. The impact of the third order dispersion, the higher-order nonlinear terms self-steepening, and stimulated Raman scattering are explicitly analyzed.