Farres P. Mattar

Double self‐induced‐transparency (SIT) in three‐level absorbers

The goal of this communication is to show that different transmission characteristics are obtained for each pulse shape when diffraction is accounted for even if the time‐integrated areas are equal. For weakly overlapped two‐field propagation it was argued that each pulse evolution obeys its own area theorem. In our case the pulses are strongly overlapped and they mutually influence each other. We have worked out the transverse variation beyond the physical situation where a specific self‐similar Gaussian mode can be assumed. Detailed temporal and frequency reshaping of coherent pulses with finite beam extent in a three‐level absorber is reported.

Control of Raman‐like coherent on‐resonant solitons

The formation of on‐resonant Raman‐like pump and probe solitons is examined to extract its characterizing features and define the physical condition suitable for its occurrence.

Transverse on‐resonance asymptotic reshaping in coherent probe soliton formation in a three‐level system

The coherent frequency conversion between on‐resonance pump and probe beams is examined in the physical situation where the nonlinear gain balances the diffraction for the probe transition. The semiclassical paraxial‐Maxwell‐Bloch formalism is adopted as introduced in propagational studies in two‐level Self‐Induced‐Transparency (SIT)[1]. The probe builds up from an input deterministic seed. The asymptotic stabilization of the probe area is reported in conjunction with pump depletion and diffraction rigorously accounted for. Without diffraction the soliton does not appear. The Laplacian term (which describes transverse coupling) is included.

Transverse on‐resonance reshaping in coherent pump soliton asymptotic evolution in a three‐level system

The coherent frequency conversion between on‐resonance pump and probe beams is examined in the physical situation where the medium nonlinearity balances diffraction for the pump transition. The probe soliton is destroyed and a pump soliton is formed. This pump depletion reversal is reported in a self‐consistent semi‐classical calculation in which diffraction is rigorously accounted for.

Physical mechanisms in coherent on‐resonance propagation of two different‐wavelength beams in a three‐level system

The coherent energy transfer from a strong pump beam at a given frequency to an initially weak probe beam injected at another frequency is reported. This exchange is achieved optimally by matching velocities to maintain maximum pulse overlap throughout the motion. The central role of pump depletion, transverse effects and time‐dependent phase variations in the co‐propagation in a medium is revealed.

Rabi‐side bands generation in optically thick medium

By adopting phase‐integral methods we compute how an off‐resonant probe coherently extracts more energy from an on‐resonance pump in an optically thick three‐level atom than a resonant probe from a larger pump. In both situations the time‐integrated area of the pump must exceed 5π. The population accumulated in the intermediate level exhibits a peak at a detuning equal to the pump Rabi frequency. This is a generalization of the Rabi side bands since propagation effects are accounted for. The pulse shape or pulse length affects the interaction.

Transition from superfluorescence (SF) to amplified spontaneous emission (ASE): A computational experiment

A semiclassical formalism with quantum initiation and an additional Langevin fluctuation source is described. It has been successfully implemented.

Transient Effects, Transverse Mode Coupling, And Diffraction In Swept-Gain Superradiance In The Nonlinear Regime: Evolution From The Superradiant State

Results of numerical calculations are presented and analyzed for pulse generation and propagation in one-and two-spacial dimensions in a medium consisting of a collection of two-level atoms which are resonantly swept-excited by an impulse excitation traveling at the speed of light in the medium. The conditions imposed for the calculation in one-spacial dimension are that T1 = T2, where T1 and T2 are the single atom relaxation and dephasing times, respectively, and that the gain, g, to loss, κ , ratio g/κ >> 1 , which determines the non-linear regime for pulse evolution. In addition, we impose that T2 >> τc, where τc is the characteristic superradiance cooperation time, so that the pulse evolves from conditions appropriate for superradiant pulse generation for sufficiently small values for the propagation distance z . We report and analyze calculational results for the transient regime of pulse buildup through the asymptotic regime of large propagation distance z where the pulse generated exhibits steady-state behavior with regard to pulse area, energy and intensity profile. Additional results of computations are presented which incorporate transverse effects and diffraction using a Gaussian radial gain profile for the initial condition and under imposed conditions comparable with those of the corresponding one-spacial dimension calculations. The results of the two sets of calculations are compared and discussed. We demonstrate and give predictive requirements for swept-gain pulse evolution from the superradiant state.

Effects Of Propagation, Transverse Mode Coupling, Diffraction, And Fluctuations On Superfluorescence Evolution

Using proven computational methods developed to efficiently treat transverse and longitudinal dynamic reshaping associated with single-stream propagation effects in cooperative light-matter interactions, a realistic superfluorescence (SF) theory was constructed in close collaboration with experimentalists. A semi-classical model based on the Maxwell-Bloch equa-tions (which rigorously encompasses diffraction, transverse density variations and inhomoge-neous broadening) is used. Furthermore, the medium initiation is stimulated by a coherent pulse of an area θ0 which varies radially, propagates along the rod axis and tips the indi-vidual Bloch vectors over an angle θ0 from its upright position. This effective initiation is treated in using either (a) an homogeneous average tipping angle or (b) instantaneous longitudinal and transverse fluctuations. The Cs datas are correctly simulated for the first time.* Important remark At this time, I wish to express my appreciation and give credit to Gibbs, McCall and Feld for their many contributions in the form of numerous relevant discussions, preparatory ana-lytical work and help in selecting details of realistic models based on their close contact with laboratory results. In addition, Dr Gibbs participation in carrying the calculations accelerated the rate of progress in my research. Let me take this occasion to thank Dr. Gibbs, Dr. McCall and Dr. Feld for their energetic and enthousiastic collaboration.