Nonlinear tuning of a set of lasers

Golubentsev, A. A.; Likhanskiǐ, V. V.; Napartovich, A. P.

doi:10.1070/qe1989v019n04abeh007896

Cited by 24 publications

(24 citation statements)

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“…The study of fluctuation effects was extended also to dynamic disorder in which the scatterers move at random. Golubentsev showed that the contribution of interference back-scattering to static field auto-correlator (in particular, average intensity), which is essential for immobile scatterers, is suppressed when they move [9]. The similar result for temporal-spatial auto-correlator (dynamic coherence function) was obtained by Stephen [10].…”

Section: Introductionsupporting

confidence: 56%

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Long-time asymptotic of temporal-spatial coherence function for light propagation through time dependent disorder

Auslender

1997

Physics Letters A

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Long-time asymptotic of field-field correlator for radiation propagated through a medium composed of random point-like scatterers is studied using Bete-Salpeter equation. It is shown that for plane source the fluctuation intensity (zero spatial moment of the correlator) obeys a power-logarithmic stretched exponential decay law, the exponent and preexponent being dependent on the scattering angle. Spatial center of gravity and dispersion of the correlator (normalized first and second spatial moments, respectively) prove to weakly diverge as time tends to infinity. A spin analogy of this problem is discussed.

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Section: Introductionsupporting

confidence: 56%

“…In two simplest, but practically important, cases of ballistic and diffusive motion: 2J = (t/τ a ) a , where a = 2 and a = 1, respectively. The formulas for time constants τ a are found, for example, in [9,10]. Thus, at t → ∞ the fluctuations decay according to power-logarithmic stretched exponential law…”

Section: Fluctuations Intensitymentioning

confidence: 99%

Long-time asymptotic of temporal-spatial coherence function for light propagation through time dependent disorder

Auslender

1997

Physics Letters A

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“…Close to an atomic resonance of width Γ, the average time an atom takes to scatter a photon is Γ −1 . If, in the meantime, atoms move by more than an optical wavelength, then the interference term between direct and reverse scattering sequences will be spoiled [28]. To avoid this, we require the spread v of the atomic velocity distribution to satisfy…”

Section: Amplitudes For Scattering Of Light By Atomsmentioning

confidence: 99%

“…Using ε =x 1 = x 4 and ε ′ = x 2 =x 3 in (34), the internal average (28) for the single scattering contribution becomes…”

Section: The Single Scattering Contributionmentioning

confidence: 99%

Weak localization of light by cold atoms: The impact of quantum internal structure

et al. 2001

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Since the work of Anderson on localization, interference effects for the propagation of a wave in the presence of disorder have been extensively studied, as exemplified in coherent backscattering (CBS) of light. In the multiple scattering of light by a disordered sample of thermal atoms, interference effects are usually washed out by the fast atomic motion. This is no longer true for cold atoms where CBS has recently been observed. However, the internal structure of the atoms strongly influences the interference properties. In this paper, we consider light scattering by an atomic dipole transition with arbitrary degeneracy and study its impact on coherent backscattering. We show that the interference contrast is strongly reduced. Assuming a uniform statistical distribution over internal degrees of freedom, we compute analytically the single and double scattering contributions to the intensity in the weak localization regime. The so-called ladder and crossed diagrams are generalized to the case of atoms and permit to calculate enhancement factors and backscattering intensity profiles for polarized light and any closed atomic dipole transition.

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“…The effect of time-dependent perturbations on transport phenomena in disordered systems has been studied in various contexts, such as the destruction of localization, 1) the suppression of the interference effect, 2) and the effect of temperature.…”

mentioning

confidence: 99%

Time-Dependent Perturbation in Two-Dimensional Disordered Symplectic Systems: Dephasing and Scaling

2003

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The effect of time-dependent perturbations on transport phenomena in disordered systems has been studied in various contexts, such as the destruction of localization, 1) the suppression of the interference effect, 2)and the effect of temperature. 3)In general, timedependent perturbations destroy the phase coherence. In fact, a numerical study of the dephasing effect by a time-dependent perturbation in two-dimensional disordered systems has been performed by Nakanishi et al. 4)They have investigated the effect of the timedependent on-site potential oscillating with a frequency ω and demonstrated that the ω-dependent correction to the conductivity takes an universal form in the metallic regime. In the present work, we study a different type of time-dependent perturbation, namely the timedependent transfer-integrals. It is expected that this type of perturbation is more representative for the effect of temperature.We consider a two-dimensional disordered system with spin-orbit interaction, which belongs to the symplectic universality class.5) The system exhibits the Anderson transition 6, 7) even in two dimensions. We numerically evaluate the conductivity as a function of the frequency of the perturbation using the equation of motion method. In the metallic regime, it is examined whether the universal ω-dependent correction to the conductivity can be observed also for the present type of perturbation. For the critical regime, we find that the frequency dependence of the conductivity can be described by the one-parameter scaling.The model we adopt is the Ando model 8) extended to the case where transfer-integrals oscillate with a frequency ω. The Hamiltonian is given by To examine the diffusion of an elecrton in such a system, we solve the time-dependent Schrödinger equation numerically using the method based on the decomposition formula for the exponential operators.9, 10) Numerical simulation is performed with the system size 299 × 299. To prepare the initial wave packet, we carry out numerical diagonalization for a sub-system of radius L = 21 located at the center of the system. Then the eigenstate having the eigenvalue closest to E F /V = −1 is assumed to be the initial wave packet. The time step is set to be δt = 0.2 /V . The quantity we observe is the second cumulant of the wave packet defined byIf the time evolution of the wave packet can be described by the diffusion equation, the second cumulant would grow in proportion to time t as (∆r(t)) 2 = 4Dt, where D is the diffusion coefficient. The conductivity σ is estimated from the diffusion coefficient D using the Einstein relation σ = e 2 ρ(E F )D, where ρ(E F ) is the density of states at the Fermi energy.First, we consider the metallic regime. In Fig. 1, we show the ω-dependence of the conductivity when ∆V Since it has also been obtained for the case of oscillating on-site random potential, 4) it is suggested that this correction to the conductivity is universal in the metallic regime for the two-dimensional symplectic systems. The present universality of th...

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Nonlinear tuning of a set of lasers

Cited by 24 publications

References 0 publications

Long-time asymptotic of temporal-spatial coherence function for light propagation through time dependent disorder

Long-time asymptotic of temporal-spatial coherence function for light propagation through time dependent disorder

Weak localization of light by cold atoms: The impact of quantum internal structure

Time-Dependent Perturbation in Two-Dimensional Disordered Symplectic Systems: Dephasing and Scaling

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