Subpicosecond Spectral Hole Burning Due to Nonthermalized Photoexcited Carriers in GaAs

The stationary nonlinear reflection and the time resolved four wave mixing signal from a molecular monolayer are calculated using Green function techniques. Cooperative resonant nonlinear response found in small aggregates suggests the existence of coherence size of order of optical wavelength. A new peak in the nonlinear reflection spectrum is predicted, which is missed by the local field approximation. For an infinite two dimensional molecular monolayer with transition dipole moments in the lattice plane, the momentum-dependent two exciton decay rate is found to be larger than the sum of the single exciton radiative decay rates, as predicted by the local field approximation.

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“…(9). Equation (16) &.ener~lizes the result of Ref. 12 in wh!ch we assumed G'=G, which is justified in the RWA.…”

Section: R~n(flm' Fln)2-3(r Mn ' Flm) (R Mn ' Fln) X--------------r-ymentioning

confidence: 97%

“…(19) and (20), we get the LFA result which is the identical to Eq. (16) except that the two exciton scattering matrix should be replaced by -(Ll r n 'n,,(Wl+W2) = -2CWl +w2-2fl)8n'n'" (21) As will be shown below, the LFA holds only when WI +wz is tuned off two exciton states.…”

Section: R~n(flm' Fln)2-3(r Mn ' Flm) (R Mn ' Fln) X--------------r-ymentioning

confidence: 98%

Cooperative ultrafast nonlinear optical response of molecular nanostructures

Wang

Chernyak

Mukamel

1994

The Journal of Chemical Physics

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“…The mathematical structure of these equations in their most compact form ((20) and ( and spin projection (r), ll = (?, a$v,+,,akv'C, v, v' = il) 9 (1.1) (for the conductmion and the valence band, respectively) closes to a direct product n @ U(2) of 2N U(2) Lie these papers evolution equations are obtained or applied which describe the atherrnal laser driven nonequilibrium in two-band systems with above or below gap excitations. Therein, the problem of Coulomb screening has not been considered, also not in ours [l to 41.…”

Section: Introductionmentioning

confidence: 99%

“…the spectral hole burning [9], the dynamical Stark effect, e.g. [lo, 111, or the dynamical band mixing, coupled to a laser-induced additional gap creation [12].…”

Section: Introductionmentioning

confidence: 99%

Screening of the Coulomb Potential in the Athermal Stage in Highly Excited Semiconductors

Heiner

1989

Physica Status Solidi (b)

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Equations for the reduced density operator are evaluated. Investigating the subdynamics of nonrelevant observables a resolvent formulation is obtained selfconsistently for the screening part of the evolution superoperator. Utilizing the diagonal representation for the time-dependent mean field term of the Hamiltonian, a selfconsistent concrete calculation of the screened potential is possible in the high density limit of the nonequilibrium. The result is an extension of the well known RPA-formula for nonequilibrium two-band systems of Fermions. An extension to the semimarkovian approximation is counted for.Ausgehend yon den Evolutionsgleichungen fur den reduzierten Dichteoperator wird die Subdynamik der nichtrelevanten Observablen in einem Resolventenformalismus untersucht. Auf diese Weise erhalt man, selbstkonsistent mit der allgemeinen Theorie, einen Ausdruck fur die Abschirmfunktion im athermalen Nichtgleichgewicht in einer zeitabhangigen Theorie des gemittelten Feldes. Die verwendete stationare Niiherung ist unter der Voraussetzung vieler Stolje auch fur das Nichtgleichgewicht anwendbar und entspricht einer Erweiterung der RPA. Eine Verbesserung der Kurzzeitgedachtnisniiherung fur den StoBterm wird angegeben.

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“…Finally, for longer times via coupling to phonons, the system relaxes back to equilibrium via cooling of hot carriers ( c ) and recombination of electron-hole pairs ( r ). In most semiconductors and their nanostructures, where th ) p for $10 fs laser pulses [14], ultrafast nonlinear photoexcitations lead to a largely nonthermal, peaked distribution close to the pump photon energy and state filling dominates on the 10 s of fs time scale [first panel, Fig. 1(b)].…”

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confidence: 99%

Stimulated Near-Infrared Light Emission in Graphene

Perakis¹

2012

Physics

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We show that strongly photoexcited graphene monolayers with 35 fs pulses quasi-instantaneously build up a broadband, inverted Dirac fermion population. Optical gain emerges and directly manifests itself via a negative conductivity at the near-infrared region for the first 200 fs, where stimulated emission completely compensates absorption loss in the graphene layer. Our experiment-theory comparison with two distinct electron and hole chemical potentials reproduce absorption saturation and gain at 40 fs, revealing, particularly, the evolution of the transient state from a hot classical gas to a dense quantum fluid with increasing the photoexcitation.

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Subpicosecond Spectral Hole Burning Due to Nonthermalized Photoexcited Carriers in GaAs

Cited by 315 publications

References 13 publications

Cooperative ultrafast nonlinear optical response of molecular nanostructures

Cooperative ultrafast nonlinear optical response of molecular nanostructures

Screening of the Coulomb Potential in the Athermal Stage in Highly Excited Semiconductors

Stimulated Near-Infrared Light Emission in Graphene

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