Related papers: Nonlinear spectroscopy of collective modes in exci…
We study the dynamics of excitonic insulators coupled to phonons. Without phonon couplings, the linear response is given by the damped amplitude oscillations of the order parameter with frequency equal to the minimum band gap. A phonon…
We consider a two-band spinless model describing an excitonic insulator (EI) on the two-dimensional square lattice with anisotropic hopping parameters and electron-phonon (el-ph) coupling, inspired by the EI candidate Ta$_2$NiSe$_5$. We…
The elementary optical excitations in two dimensional semiconductors hosting itinerant electrons are attractive and repulsive polarons -- excitons that are dynamically screened by electrons. Exciton-polarons have hitherto been studied in…
Motivated by recent interests in exploring excitonic condensate as the ground state of some narrow-bandgap semiconductors such as transition metal dichalcogenides and layered chalcogenide material Ta$_2$NiSe$_5$, in this work we…
We show that the nonlinear optical response probed by two-dimensional coherent spectroscopy (2DCS) can discriminate between excitonic and lattice driven order. In the excitonic regime of a realistic model of Ta$_2$NiSe$_5$, the third order…
The recent observation of a transmitted Thz pulse oscillating at three times the frequency of the incident light paves the way to a new protocol to access resonant excitations in a superconductor. Here we show that this non-linear optical…
We explore the collective response in an excitonic insulator phase in Ta$_2$NiSe$_5$ using a semirealistic model including relevant lattice and electronic instabilities. We calculate order-parameter susceptibility and Raman response within…
We consider nonlinear effects in scattering of light by a periodic structure supporting optical bound states in the continuum. In the spectral vicinity of the bound states the scattered electromagnetic field is resonantly enhanced…
The strong-field induced generation of nonclassical states of light is not only a subject of fundamental research but also has potential usage in quantum information science and technology. The emerging field of strong-field quantum optics…
Optical responses of atomically thin 2D materials are greatly influenced by electron-hole interactions. It is by far established that exciton signatures can be well-identified in the optical absorption spectrum of quasi-2D materials.…
Excitonic insulator is a coherent electronic phase that results from the formation of a macroscopic population of bound particle-hole pairs - excitons. With only a few candidate materials known, the collective excitonic behavior is…
We report about the experimental observation and characterization of nonlinear optical properties of individual silicon nanowires of different dimensions. Our results show that the nonlinear light has different components, one of them…
Exciton effects on conjugated polymers and the resulting optical nonlinearities are investigated in soliton lattice systems. The magnitude of the THG at the 10 percent doping increases by the factor about 10^2 from that of the neutral…
Nonlinear light propagation in a single-mode micron-size waveguide made of semiconducting excitonic material has been theoretically studied in terms of exciton-polaritons by using an analysis based on macroscopic fields. When a light pulse…
We employ time-resolved resonant x-ray diffraction to study the melting of charge order and the associated insulator-metal transition in the doped manganite Pr$_{0.5}$Ca$_{0.5}$MnO$_3$ after resonant excitation of a high-frequency…
We predict a non-thermal magneto-optical effect for magnetic insulators subject to intense light carrying orbital angular momentum (OAM). Using a classical approach to second harmonic generation in non-linear media with specific symmetry…
We theoretically investigate the nonlinear optical pulse responses of excitons in a thin film where the excitonic center-of-mass motion is confined. A large interaction volume between excitons and radiation yields particular coupled states…
Excitonic effects in the linear optical response of semiconductors are well-known and the subject of countless experimental and theoretical studies. For the technologically important second order nonlinear response, however, description of…
The amplitude and phase of a material's nonlinear optical response provide insight into the underlying electronic dynamics that determine its optical properties. Phase-sensitive nonlinear spectroscopy techniques are widely implemented to…
Optical responses in an excitonic insulating (EI) system with strong electron correlation are studied. We adopt the two-orbital Hubbard model with a finite energy difference between the two orbitals where the spin state degree of freedom…