Related papers: Two-phonon infrared processes in semiconductors
We present an \textit{ab initio} study based on density-functional theory of first- and second-order Raman spectra of graphene-based materials with different stacking arrangements and numbers of layers. Going from monolayer and bilayer…
We use density functional theory to calculate the electronic band structures, cohesive energies, phonon dispersions, and optical absorption spectra of two-dimensional In$_2$X$_2$ crystals, where X is S, Se, or Te. We identify two…
Resonance Raman scattering, which probes electrons, phonons and their interplay in crystals, is extensively used in two-dimensional materials. Here we investigate Raman modes in MoSe$_2$ at different laser excitation energies from 2.33 eV…
We study the infrared conductivity of graphene at finite chemical potential and temperature taking into account the effect of phonons and disorder due to charged impurities and unitary scatterers. The screening of the long-range Coulomb…
We calculate the double resonant (DR) Raman spectrum of graphene, and determine the lines associated to both phonon-defect processes, and two-phonons ones. Phonon and electronic dispersions reproduce calculations based on density functional…
We have investigated the infrared and Raman optical properties of BaMn2As2 in the ab-plane and along the c-axis. The most prominent features in the infrared spectra are the Eu and A2u phonon modes which show clear TO-LO splitting from the…
We present a detailed calculation of intensities of two-phonon and four-phonon Raman peaks in graphene. Writing the low-energy hamiltonian of the interaction of electrons with the crystal vibrations and the electromagnetic field from pure…
We study the semigroup of the symmetric $\alpha$-stable process in bounded domains in $\R^2$. We obtain a variational formula for the spectral gap, i.e. the difference between two first eigenvalues of the generator of this semigroup. This…
The phonon-assisted interband optical absorption spectrum of silicon is calculated at the quasiparticle level entirely from first principles. We make use of the Wannier interpolation formalism to determine the quasiparticle energies, as…
Spectra of the degenerate two-photon absorption coefficient $\beta(\omega)$, anisotropy parameter $\sigma(\omega)$, and dichroism parameter $\delta(\omega) = \big[\sigma(\omega) + 2\eta(\omega)\big]/2$ of crystalline 110-cut GaAs, GaP, and…
Two-photon processes have so far been considered only as resulting from frequency-matched second-order expansions of light-matter interaction, with consequently small coupling strengths. However, a variety of novel physical phenomena arises…
Gallium phosphide is an important indirect band gap material with variety of applications in optics ranging from LEDs to applications in GaP/Si based solar cells. We investigated GaP using ultrafast, pump-probe coherent acoustic phonon…
We theoretically investigate the double-resonance Raman spectrum of monolayer graphene down to infrared laser excitation energies. By using first-principles density functional theory calculations, we improve upon previous theoretical…
We report on interferometric autocorrelation measurements of broadband supercontinuum light in the anomalous dispersion regime using two-photon absorption in a GaP photodetector. The method is simple, low-cost, and provides a direct measure…
The shifts of the electronic absorption spectra of GaAs and GaP semiconductor clusters are calculated using accurate pseudopotentials. In the absence of experimental data at present, these calculations provide estimates of expected spectral…
A theoretical investigation is made of the dispersion characteristics of plasmons in a two-dimensional periodic system of semiconductor (dielectric) cylinders embedded in a dielectric (semiconductor) background. We consider both square and…
We theoretically study the optical properties of an InAs/GaAs quantum dot (QD) near the area of the second-order resonance between an electron confined in the QD and two longitudinal optical phonons. We present the absorption spectra of an…
We report the first experimental observations of two-photon emission from semiconductors, to the best of our knowledge, and develop a corresponding theory for the room-temperature process. Spontaneous two-photon emission is demonstrated in…
Phonon mean free path is generally inferred from the measurement of thermal conductivity and we are still lacking precise information on this quantity. Recent advances in the field of high frequency phonons transduction using semiconductor…
The photoresponse of graphene at mid-infrared frequencies is of high technological interest and is governed by fundamentally different underlying physics than the photoresponse at visible frequencies, as the energy of the photons and…