Quantum Coherence in an Optical Modulator

Carter, Sam; Birkedal, Victoria; Wang, C. S.; Coldren, L.A.; Maslov, A. V.; Citrin, D. S.; Sherwin, Mark S.

doi:10.1126/science.1116195

Cited by 116 publications

(58 citation statements)

References 19 publications

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“…19 The recent progress in THz light sources has encouraged experimental studies of coherent control of excitonic states in undoped SLs with a relatively weak THz field. [20][21][22][23][24][25][26][27][28] Further, the development of higher-power THz light sources with a peak intensity of the order of hundreds of kV/cm and above [29][30][31] enables one to investigate the unexplored research area of the Floquet exciton under consideration here; this exciton is composed of a photodressed electron-hole pair, each carrier of which is generated by THz-wave irradiation. Thus far, a number of theoretical studies have been devoted to revealing the anomalous behavior of such excitonic states regarding negative absorption (optical gain).…”

Section: Introductionmentioning

confidence: 99%

Dynamical Fano resonance of an exciton in laser-driven semiconductor superlattices

Maeshima

Hino

2012

Phys. Rev. B

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An excitonic Floquet state in semiconductor superlattices (SLs) driven by an intense monochromatic laser is examined based on multichannel scattering theory, where this state is supported by a photon sideband attributed to a SL joint miniband. It is shown that the excitonic Fano resonance (FR) is caused by the coupling between photon sidebands, and thus one obtains the possibility of dynamic quantum control of this exciton state by means of laser tuning. This FR differs from the conventional FR observed in the original SLs without laser irradiation in that the latter FR results from the static Coulomb coupling between different SL joint minibands. Both the q parameter and the spectral width associated with the excitonic FR of concern vary notably with a change of laser strength. In particular, it is found that the FR is made stable, that is, 1/|q| and become minimized, when the laser strength is appropriately tuned to the condition of what is called dynamic localization.

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Section: Introductionmentioning

confidence: 99%

Dynamical Fano resonance of an exciton in laser-driven semiconductor superlattices

Maeshima

Hino

2012

Phys. Rev. B

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“…The advent of sources of intense terahertz electromagnetic radiation enables the study of semiconductors in a regime where time-dependent perturbation theory fails completely. Exciting new quantum coherent phenomena emerge, including the dynamical Franz-Keldysh effect [6,7], non-linear excitonic effects [8][9][10][11], and highorder sideband generation [12][13][14]. High-order sideband generation is a cousin of high-order harmonic generation from atoms in intense laser fields [15][16][17].…”

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confidence: 99%

Terahertz Electron-Hole Recollisions inGaAs/AlGaAsQuantum Wells: Robustness to Scattering by Optical Phonons and Thermal Fluctuations

et al. 2013

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Electron-hole recollisions are induced by resonantly injecting excitons with a near-IR laser at frequency fNIR into quantum wells driven by a 10 kV/cm field oscillating at fTHz = 0.57 THz. At T = 12 K, up to 18 sidebands are observed at frequencies f sideband = fNIR + 2nfTHz, with −8 ≤ 2n ≤ 28. Electrons and holes recollide with total kinetic energies up to 57 meV, well above the ELO = 36 meV threshold for longitudinal optical (LO) phonon emission. Sidebands with order up to 2n = 22 persist up to room temperature. A simple model shows that LO phonon scattering suppresses but does not eliminate sidebands associated with kinetic energies above ELO.The interaction of electrons and holes in semiconductors has long been a rich area of study in physics. In most cases, the electron and hole are treated as point particles within the effective mass approximation [1]. In this approximation, the effects of the lattice are parametrized by the dielectric constant of the semiconductor and the effective masses of the electrons and holes. Calculations based on the effective mass approximation successfully predict, for example, the binding energies and the frequencies of internal transitions of impurity-bound electrons and excitons in GaAs [2] and in GaAs/AlGaAs quantum wells [3][4][5]. The effective mass approximation, however, belies the rich complexity of the microscopic physics. In GaAs, for example, ground-state excitons are collective excitations of more than 10 5 atoms in the crystal. The advent of sources of intense terahertz electromagnetic radiation enables the study of semiconductors in a regime where time-dependent perturbation theory fails completely. Exciting new quantum coherent phenomena emerge, including the dynamical Franz-Keldysh effect [6,7], non-linear excitonic effects [8][9][10][11], and highorder sideband generation [12][13][14]. High-order sideband generation is a cousin of high-order harmonic generation from atoms in intense laser fields [15][16][17]. Excitons are created by a near-infrared laser in a semiconductor driven by an intense terahertz field. The terahertz field ionizes the exciton into an electron and a hole that it then pulls apart and smashes back together. Upon recollision, the electron and hole can recombine across the band gap with the acquired kinetic energy carried off by light with frequency above that of the near-IR laser.In this Letter, we report that the electron-hole recollision process-which, in its theoretical descriptions to date has been treated as a purely ballistic process-is surprisingly robust against scattering. We report electronhole recollisions both with kinetic energy well above the threshold for emission of a longitudinal optical (LO) phonon and at room temperature. We model our results by treating the electron-hole pair as a single particle with the appropriate reduced mass subject to dephasing and LO phonon scattering.Two quantum well (QW) samples with 20 QW repetitions were studied. Both samples were grown on semiinsulating GaAs substrates by molecular beam epitax...

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“…Recently, the fast development of the terahertz technology [21,22] has made it possible to obtain an extremely strong and long-wavelength THz field [23,26]. Based on this, a new scheme with the coherent THz control to HHG generation has been put forward and widely investigated [24][25][26][27].…”

Section: Introductionmentioning

confidence: 99%

Quantum path control on the harmonic emission in the presence of a terahertz field

Feng¹,

Chu²

2012

Chemical Physics

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Quantum Coherence in an Optical Modulator

Cited by 116 publications

References 19 publications

Dynamical Fano resonance of an exciton in laser-driven semiconductor superlattices

Dynamical Fano resonance of an exciton in laser-driven semiconductor superlattices

Terahertz Electron-Hole Recollisions inGaAs/AlGaAsQuantum Wells: Robustness to Scattering by Optical Phonons and Thermal Fluctuations

Quantum path control on the harmonic emission in the presence of a terahertz field

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