Nonlinear optics of semiconductor and molecular nanostructures; a common perspective

Axt, Vollrath M.; Mukamel, Shaul

doi:10.1103/revmodphys.70.145

Cited by 244 publications

(320 citation statements)

References 177 publications

(214 reference statements)

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“…The CEO thus offers a unified description of different materials and allows a direct comparison of their optical properties (33). Also, one can go beyond the PPP Hamiltonian and the TDHF approximation and include additional variables and use a different ansatz for the wave function (34).…”

Section: Discussion and Other Applicationsmentioning

confidence: 99%

Electronic Coherence and Collective Optical Excitations of Conjugated Molecules

Mukamel

Tretiak

Wagersreiter

et al. 1997

Science

350

354

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Optical spectroscopy of conjugated molecules is described by using collective electronic coordinates, which represent the joint dynamics of electron-hole pairs. The approach relates the optical signals directly to the dynamics of charges and bond orders (electronic coherences) induced by the radiation field and uses only ground-state information, thus avoiding the explicit calculation of excited molecular states. The resulting real-space picture is reminiscent of the normal-mode analysis of molecular vibrations and offers a unified framework for the treatment of other types of systems including semiconductor nanostructures and biological complexes. Spatial coherence displayed in two-dimensional plots of the five electronic normal modes that dominate the optical response of poly( p-phenylene vinylene) oligomers with up to 50 repeat units (398 carbon atoms) in the 1.5-to 8-electronvolt frequency range suggests a saturation to bulk behavior at about five repeat units. Spectroscopy allows chemists and physiciststo probe of the dynamics of vibrations and electronic excitations within molecules and solids. The theoretical models used for interpreting molecular spectra compared with those for extended solids are usually quite different, and certain systems, such as clusters and polymers, are not readily treated by either of these limiting cases. There is particular interest to understand the optical spectra of large polymers, which are extended conjugated molecules such as poly(p-phenylene vinylene) (PPV) oligomers (Fig. 1) that have interesting optical applications.Electronic and optical properties of small conjugated chains can be interpreted molecularly in terms of their global manyelectron eigenstates obtained from quantum-chemistry methods (1, 2). Large polymers also can be analyzed with semiconductor band theories that focus on the dynamics of electron-hole pairs (3). The size-scaling of the optical response and the transition between these two regimes has not been fully explored for the lack of adequate theoretical methods. It is very hard to obtain the complete set of eigenstates, which carry considerably more information than necessary for the calculation of spectra, for large molecules with strong electron correlations (as occurs in conjugated chains). Band theories, however, neglect electronic correlation effects, and because they are formulated in momentum (k) space, they do not lend themselves easily to real-space chemical intuition.The collective-electronic oscillator (CEO) representation (4, 5) provides a hybrid formulation that bridges the gap between the chemical and semiconductor points of view. This model uses an electronhole picture in real space, overcomes many of the difficulties associated with the former approaches, and provides a physically intuitive link between electronic structure and optical properties, that is, the optical properties are related directly to the motions of charges and electronic coherences, thus avoiding the need to calculate the global (many-electron) eigenstates. The elec...

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Section: Discussion and Other Applicationsmentioning

confidence: 99%

Electronic Coherence and Collective Optical Excitations of Conjugated Molecules

Mukamel

Tretiak

Wagersreiter

et al. 1997

Science

350

354

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“…σ + ) polarization, thus excluding the coherent excitation of bound two-pair coherences (biexcitons). We start from the Heisenberg equations for the exciton polarization and cavity field describing quantum optical effects and coherent nonlinear optics in SMCs [7], where the hierarchy of higher order density matrices has been closed by invoking the dynamics controlled truncation (DCT) scheme [8]. The variables describing two-pair transitions can be eliminated by formally inverting the corresponding equations of motion.…”

Section: Many-body and Correlation Effects In Semiconductor Microcavimentioning

confidence: 99%

Coherence and correlation in semiconductor microcavities

Stefano¹,

Savasta²,

Girlanda³

2004

Laser Phys. Lett.

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Abstract:We present an overview of our results concerning the influence of two-pair continuum coherences on the transient nonlinear optical response of semiconductor microcavities. We show that the interplay between these 4-particle coherences and the nonperturbative light-matter interaction produces highly desirable almost decoherence-free exciton-exciton collisions on the lower polariton branch. This effect gives rise to the very different nonlinear absorption rates on the two polariton branches observed in many experiments and make possible to reach a very high degree of amplification in samples with large Rabi splitting. Moreover, we show that the availability of almost decoherence free exciton-exciton collisions can be used for the realization of coherent trapping of polariton emission and amplification. This coherent manipulation and trapping of many-particle polariton states can be performed employing both ultrafast and continuous wave operation. The power dependence of the integrated gain

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“…The Coulomb interaction is treated on the basis of Hartree-Fock approximation. The neglected genuine many-body correlation [17] may lead to almost instantaneous decay in time-integrated (TI) FWM signals, which is irrelevant to the intrinsic dephasing [5]. This effect is crucial for the magneto-confined FR [5] due to the magnetic field-induced enhancement of many-body correlation [18], but is less important for the decay of TI-FWM signals in biased SSL's, which is, in essence, an intrinsic dephasing process [3,19].…”

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confidence: 99%

Dynamic Fano resonance of Floquet-state excitons in superlattices

Liu

Zhu

2000

J. Phys.: Condens. Matter

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The dynamic Fano resonance (DFR) between discrete quasienergy excitons and sidebands of their ionization continua is predicted and investigated in dc-and ac-driven semiconductor superlattices. This DFR, well controlled by the ac field, delocalizes the excitons and opens an intrinsic decay channel in nonlinear four-wave mixing signals.PACS numbers: 71.35. Cc, 42.50.Md, 78.20.Jq, 78.47.+p The Fano resonance (FR) results from quantum coupling between a discrete state and a degenerate continuum of states and manifests itself in optical spectra as asymmetric lineshape [1]. FR was observed in a variety of atomic and molecular systems. Recently, this phenomenon has been reported in semiconductor quantum wells [2], in biased semiconductor superlattices (SSL's) [3], and in bulk GaAs in the presence of magnetic field [4,5] where discrete excitons couple to continua of the lower transitions through Coulomb interaction [6]. In addition to the frequency-domain experiments, transient four-wave mixing (FWM) in magneto-confined bulk semiconductors [5] and in SSL's [3] has demonstrated that the FR is a fundamental type of dephasing mechanism in irreversible quantum dynamical processes.An intense ac field, e.g. the free electron laser, can induce the dynamical localization (DL) [7] of electrons in SSL's. The DL is directly related to the collapse of the quasienergy band of Floquet states [8][9][10], the temporal analogue to the Bloch states in spatially periodic potential [11]. Research taking into account Coulomb interaction has shown that the DL may cause the dimension crossover of excitons [12] and the enhancement of exciton binding and opacity in linear [12,13] and nonlinear spectra [14]. Meanwhile the dynamical delocalization (DDL) effect of an ac field is also investigated on localized Wannier-Stark (WS) states [15] in biased SSL's [9,10,14], which is hindered by Coulomb binding [14].In this Letter, we predict the dynamic Fano resonance (DFR) between quasienergy exciton states in biased SSL's driven by an intense THz-field. In particular, the novelty of this DFR consists in the coupling between the discrete quasienergy exciton and the neighbor sideband of its ionization continuum. This DFR will also lead to the dynamical ionization of bound excitons in SSL's, which itself is a new effect of the ac field.The one-dimensional tight-binding model [14,16] is adopted in the present investigation. With excluding the realistic three-dimensional excitonic motion, the results are hardly compared to experimental data quantitatively, but we believe this simple model does present qualitatively correct results, in view of the fact that the ground WS exciton-state usually possesses much larger oscillator strength than its ionization continuum of inplane motion, and the coupling induced by the ac field between the in-plane motion associated with different WS states is negligible because of their approximate orthogonality. The Coulomb interaction is treated on the basis of Hartree-Fock approximation. The neglected genuine many-body corr...

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Nonlinear optics of semiconductor and molecular nanostructures; a common perspective

Cited by 244 publications

References 177 publications

Electronic Coherence and Collective Optical Excitations of Conjugated Molecules

Electronic Coherence and Collective Optical Excitations of Conjugated Molecules

Coherence and correlation in semiconductor microcavities

Dynamic Fano resonance of Floquet-state excitons in superlattices

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