Self-induced transparency in self-chirped media

Stroud, C. R.; Bowden, Charles M.; Allen, L.

doi:10.1016/0030-4018(88)90033-8

Cited by 52 publications

(22 citation statements)

References 14 publications

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“…Friedberg, Hartmann, and Manassah [10] have shown that under conditions of nonlinear response the value of the Lorentz shift depends upon the degree of population inversion between the two interacting levels. The implications of this inversion-dependent frequency shift on intrinsic optical bistability [11] and on the propagation of optical solitons [12] have been examined.…”

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confidence: 99%

Linear and nonlinear optical measurements of the Lorentz local field

et al. 1991

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We have studied the resonant optical response of a dense atomic potassium vapor under conditions such that the response is strongly influenced by local-field effects. Our experimental results are in good agreement with the predictions of theory. We have also discovered a collision-induced shift of the potassium resonance lines given by Acoco\=^PN, where ^= -5.0x 10~^ sec"'cm^ for the 4^5*1/2^^4 ^P1/2 transition and where )3= -3.0x 10 ~^ sec""'cm^ for the 4 ^51/2^^4 ^^3/2 transition. PACS numbers: 42.65. Bp, 03.50.De, 32.70.Jz, 42.65.Hw One of the fundamental problems of optical physics concerns the proper procedure for relating macroscopic properties of material systems, such as susceptibilities and refractive indices, to microscopic properties, such as atomic and molecular polarizabilities [1][2][3]. The proper treatment of this problem is extremely difficult, because in principle each atom of the sample interacts with every other atom, and all of these interactions must be accounted for in describing the macroscopic properties of the material. One of the standard but approximate procedures for accounting for these interactions is to introduce the concept of the local field Eioc-The local field is taken to be the effective field, due both to external sources and to all other atoms of the material sample, that acts on a typical atom of the material. The local field is to be distinguished both from the microscopic electric field and from the macroscopic field E, which is the averaged microscopic field and which is the field that appears in the macroscopic Maxwell equations. According to a prescription described by Lorentz [4], the local and macroscopic fields within a isotropic environment are related (in Gaussian units) bywhere P denotes the polarization of the material system. For the case of a material with a purely linear response, the polarization can be taken to have the form P =7VaEioc, where TV represents the number density of atoms and a represents the atomic polarizability. If we define the dielectric constant in the conventional manner so that 6=^1+4;r;^, where the linear susceptibility is defined by the relation P=;^E, we find from Eq. (l) that 6 satisfies the well-known Lorentz-Lorenz law [4]^-1 _ 4;r ^, 6+2 3(2)The Lorentz-Lorenz law can be written alternatively as 6 = l+4;rL7Va, where the local-field enhancement factor L==(6 + 2)/3 can be interpreted as the factor by which the material response e~-\ exceeds the predicted value when calculated in the absence of local-field effects.Local-field effects also play an important role in determining the magnitude of the nonlinear response of optical materials [5]. For example, within the above framework, Bloembergen [6] has shown that the third-order susceptibility X ^^^^4'y(03,(02,co\) of a collection of polarizable molecules is given by X^^^='L(co4)L(co3)L((02)L(coONy^^\ (3)where y (co4;a)3,co2,o)]) is the molecular hyperpolarizability. Note that L appears to fourth order in the expression; local-field effects play an even more important role in determ...

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confidence: 99%

Linear and nonlinear optical measurements of the Lorentz local field

et al. 1991

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“…Intrinsic optical bistability (IOB) can have important device applications in optical computing and optical data processing [5]. Other effects of NDD interactions which have been analyzed include conditions for self-induced transparency (SIT) in isotropic, homogeneously broadened media [2], and selfphase modulation in SIT [3], as well as linear and nonlinear shifts in the absorption spectrum [4]. Both linear and nonlinear spectral effects due to NDD interactions have recently been observed in reAectivity spectrum measurements using a sapphire window to form an interface with a dense potassium vapor [6].…”

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Ultrafast intrinsic optical switching in a dense medium of two-level atoms

1992

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We performed a numerical investigation of the dynamics of the Bloch equations, extended for dense media (media having many atoms within a cubic resonance wavelength), for optical pulses whose duration is much less than an induced-dipole dephasing time. We find a signature of near dipole-dipole interaction which may provide a useful method for validating the first-principles model, for measuring the strength of the interaction, and for coherent pumping. Further, we demonstrate a new and unique optical switching mechanism which may lead to the development of important devices.PACS numbers: 42.65.Pc, 42.50.Hz, 42.79.Ta In dense media, of densities such that there are many atoms within a cubic atomic resonance wavelength, induced near dipole-dipole (NDD) interactions can cause a dynamic frequency chirp in the system [l-4]. In the steady-state limit, NDD interactions may cause bistability that is intrinsic to the material and does not require an external feedback mechanism [I]. Intrinsic optical bistability (IOB) can have important device applications in optical computing and optical data processing [5]. Other effects of NDD interactions which have been analyzed include conditions for self-induced transparency (SIT) in isotropic, homogeneously broadened media [2], and selfphase modulation in SIT [3], as well as linear and nonlinear shifts in the absorption spectrum [4]. Both linear and nonlinear spectral effects due to NDD interactions have recently been observed in reAectivity spectrum measurements using a sapphire window to form an interface with a dense potassium vapor [6].In this Letter, we consider optical pulses, whose temporal duration is assumed to be much less than an induced-dipole dephasing time, incident upon a thin film of homogeneously broadened material composed of twolevel atoms with NDD interactions.In this limit, the induced-dipole dephasing time and the population-decay time can be neglected. We consider the film thickness in the propagation direction to be much smaller than the atomic resonance wavelength so that propagation effects may be neglected.Under these conditions, we find that the inversion w that remains after a pulse has passed has a nearly stepfunction response to the peak value of the time-varying field, largely independent of the pulse shape and pulse area. A peak Rabi frequency, Ao=pEo/h, is associated with the peak amplitude Fo of the field envelope, where p is the matrix element of the transition dipole moment.The system, initially in the ground state, w = -I, is always returned to the ground state when the peak Rabi frequency is less than the strength of the NDD interaction~. However, the final state of the inversion is the fully excited state, w =1, when Qo is nearly equal to e. This suggests that the strength of the NDD interaction can be measured by increasing the field amplitude and interrogating the system after the pulse has passed, in a pulseprobe scenario, to determine whether the system is in the ground or excited state. Furthermore, the nearly stepfunction response of...

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“…A number of studies have been carried out regarding the propagation of extremely short pulses (ESPs) in resonant atomic medium [1, 3-5, 7, 8, 11, 16, 20]. Two level resonant approximation is seen to be inaccurate in several physical situations [5,21], like dense atomic media and systems involving three level atoms. Thus the resonant model needs to be generalized and extended to the nonresonant scenario.…”

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Propagation of Spikes in Nonresonant Atomic Media: The Reduced Maxwell-Duffing Model

Roy

Raju

Panigrahi

et al. 2021

JNMP

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We obtain spikes or extremely short pulses for reduced Maxwell-Duffing equations under a general boundary condition, connecting the electric field and electron amplitude, using a Möbius transformation. For a nonzero background, this system is shown to admit two families of exact solutions in the form of solitary waves and kink-type of solutions. Parameter domains are delineated where localized solutions signifying both bright and dark spikes, as also singular solutions indicating self-focusing effect, exist in this dynamical system, in nonresonant atomic media.

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Self-induced transparency in self-chirped media

Cited by 52 publications

References 14 publications

Linear and nonlinear optical measurements of the Lorentz local field

Linear and nonlinear optical measurements of the Lorentz local field

Ultrafast intrinsic optical switching in a dense medium of two-level atoms

Propagation of Spikes in Nonresonant Atomic Media: The Reduced Maxwell-Duffing Model

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