Related papers: Dispersion of the Third-Order Nonlinear Optical Su…
We present a calculation of Third Harmonic Generation (THG) for two-band systems using the length gauge that avoids unphysical divergences otherwise present in the evaluation of the third order current density response. The calculation is…
We derive numerical tight-binding hopping parameters to describe conduction-band dispersion in arbitrary orientational phases of $A_3$C$_{60}$. The parameters are obtained by direct Fourier inversion of the spectra from self-consistent…
We report observation of strong and anisotropic third harmonic generation (THG) in monolayer and multilayer ReS$_2$. The third-order nonlinear optical susceptibility of monolayer ReS$_2$, $\left| \chi^{(3)} \right|$ is on the order of…
We report on a comprehensive experimental and theoretical study of optical third harmonic generation (THG) on the exciton-polariton resonances in the zinc-blende semiconductors GaAs, CdTe, and ZnSe subject to an external magnetic field,…
Recent advancements in nonlinear nanophotonics are driven by the exploration of sharp resonances within high-index dielectric metasurfaces. In this work, we leverage doubly degenerate quasi-bound states in the continuum (quasi-BICs) to…
In a superconductor the third-harmonic generation (THG) of a strong THz pulse is enhanced below Tc by the resonant excitation of lattice-modulated charge fluctuations (LCF), which modulate the response according to the polarization of the…
We study third-harmonic generation (THG) in an excitonic insulator (EI) described in a two-band correlated electron model. Employing the perturbative expansion with respect to the external electric field, we derive the THG susceptibility…
We study the third-order nonlinear optical susceptibility $\chi^{(3)}$ and photoexcited states of two-dimensional (2D) Mott insulators by using an effective model in the strong-coupling limit of a half-filled Hubbard model. In the…
We compute from first principles the infrared dispersion of the nonlinear susceptibility $\chi^{(2)}$ in zincblende semiconductors. At terahertz frequencies the nonlinear susceptibility depends not only on the purely electronic response…
Nonlinear optical phenomena are at the heart of various technological domains such as high-speed data transfer, optical logic applications, and emerging fields such as non-reciprocal optics and photonic time crystal design. However,…
We present a theory for the electron-temperature dependence $T_{el}$ of optical second harmonic generation (SHG). Such an analysis is required to study the dynamics of metallic systems with many hot electrons not at equilibrium with the…
We present a combined experimental and theoretical study of enhanced third-harmonic generation (THG) in silicon nitride metasurfaces. These structures exhibit strong resonant nonlinear responses, enabling up to two orders of magnitude…
We present experimental and theoretical results for the angular dependence of third harmonic generation (THG) of water droplets in the micrometer range (size parameter $62<ka<248$). The THG signal in $p$- and $s$-polarization obtained with…
Improving the conversion efficiency is critical for advancing nonlinear photonic devices, enabling applications in ultrafast optics, quantum light sources, and high-resolution imaging. Herein, we present a bilayer waveguide integrated with…
We report on time-resolved linear and nonlinear terahertz spectroscopy of the two-band superconductor MgB$_2$ with the superconducting transition temperature $T_c \approx 36$ K. Third-harmonic generation (THG) is observed below $T_c$ by…
We theoretically investigate the resonance of third harmonic generation (THG) that has been observed at frequency being half of the superconducting gap in a multiband disordered superconductor NbN. The central question is whether the…
The effective second-harmonic generation (SHG) coefficient is a crucial data that quantifies the efficiency of transforming fundamental frequency light into its second harmonic. With the help of the symmetry of nonlinear optical…
Third-harmonic generation (THG) is a key nonlinear optical process for ultrafast imaging, terahertz (THz) signal generation, and symmetry-sensitive probes, often dominating in centrosymmetric materials where lower-order responses vanish.…
We investigate the third-harmonic generation (THG) of s-wave superconductors under microwave pulse irradiation. We consider the effect of paramagnetic impurities on the THG intensity of dirty superconductors. The nonlinear response function…
The optical excitations in C$_{60}$ and higher fullerenes, including isomers of C$_{76}$, C$_{78}$, and C$_{84}$, are theoretically investigated. We use a tight binding model with long-range Coulomb interactions, treated by the Hartree-Fock…