相关论文: Linear optical absorption spectra of mesoscopic st…
The Dynamical Franz-Keldysh Effect is exposed by exploring near-bandgap absorption in the presence of intense THz electric fields. It bridges the gap between the DC Franz- Keldysh effect and multi-photon absorption and competes with the THz…
We introduce and analyze the properties of dynamical Franz-Keldysh effect, i.e. the change of density-of-states, or absorption spectra, of semiconductors under the influence of {\it time-dependent} electric fields. In the case of a harmonic…
Franz-Keldysh effect is expressed in the smearing of the absorption edge in semiconductors under high electric fields. While Franz and Keldysh considered a limited case of externally applied uniform electric field, the same effect may be…
We applied the time-resolved attosecond transient absorption spectroscopy to systematically investigate ultrafast optical responses of condensed matter systems. Under an intense pump pulse, absorption spectra indicate that the…
The effect of a constant electric field on two-photon absorption in a semiconductor is calculated using an independent-particle theory. The theoretical framework is an extension of a theory of the one-photon Franz-Keldysh effect [Wahlstrand…
We study the linear optical absorption of bulk semiconductors in the presence of a homogeneous constant (dc) electric field with an approach suitable for including excitonic effects while working with many-band models. The absorption…
This paper applies analytical approximations for the luminescence of short period semiconductor superlattices and analyses the low density regime, demonstrating that the theory clearly connects with low density absorption with ratios of…
We formulate a time-dependent density functional theory (TDDFT) in terms of the density matrix to study ultrafast phenomena in semiconductor structures. A system of equations for the density matrix components, which is equivalent to the…
The effect of a constant electric field on two-photon absorption in a direct band gap semiconductor is calculated using an independent-particle theory. Two band structure models for GaAs are used: a two-band parabolic model and an…
We consider a generation and an amplification of THz radiation in semiconductor superlattices under the action of microwave pump field. Electrons belonging to a single miniband of the superlattice interact quasistatically with the pump…
We consider terahertz absorption and gain in a single miniband of semiconductor superlattice subject to a bichromatic electric field in the most general case of commensurate frequencies of the probe and pump fields. Using an exact solution…
We present an experimental and computational study of the nonlinear optical response of conduction electrons to intense terahertz (THz) electric field. Our observations (saturable absorption and an amplitude-dependent group refractive…
The effects of chemical disorder on the electronic and optical properties of semiconductor alloy multilayers are studied based on the tight-binding theory and single-site coherent potential approximation. Due to the quantum confinement of…
In the framework of the Keldysh technique, we formulate the nonlinear sigma model for disordered optical media with linear absorption or gain. The effective action for fluctuations of the matrix field about the saddle point acquires an…
We investigate the electro-optic properties of black phosphorus (BP) thin films for optical modulation in the mid-infrared frequencies. Our calculation indicates that an applied out-of-plane electric field may lead to red-, blue-, or…
We have theoretically investigated nonlinear free-carrier absorption of terahertz radiation in InAs/AlSb heterojunctions. By considering multiple photon process and conduction-valence interband impact ionization (II), we have determined the…
Franz-Keldysh oscillations of the optical absorption in the presence of short-range disorder are studied theoretically. The magnitude of the effect depends on the relation between the mean-free path in a zero field and the distance between…
The optical absorption of a single spherical semiconductor quantum dot in an electrical field is studied taking into account the nonlocal coupling between the field of the light and the polarizability of the semiconductor. These nonlocal…
We study the dynamical transport in weakly coupled superlattices in the presence of intense radiation in the THz regime. We derive a general model for the time dependent tunneling current within the Keldysh nonequilibrium-Green-function…
An $\it{ab \,\, initio}$ based fully microscopic approach is applied to study the nonlinear optical response of bulk Tellurium. The structural and electronic properties are calculated from first principles using the shLDA-1/2 method within…