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Related papers: Nonlinear terahertz electro-optical responses in c…

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Motivated by the ongoing controversy on the origin of the nonlinear index saturation and subsequent intensity clamping in femtosecond filaments, we study the atomic nonlinear polarization induced by a high-intensity and ultrashort laser…

Although massless Dirac fermions in graphene constitute a centrosymmetric medium for in-plane excitations, their second-order nonlinear optical response is nonzero if the effects of spatial dispersion are taken into account. Here we present…

Mesoscale and Nanoscale Physics · Physics 2016-12-07 Yongrui Wang , Mikhail Tokman , Alexey Belyanin

This paper discusses the solution of nonlinear integral equations with noisy integral kernels as they appear in nonparametric instrumental regression. We propose a regularized Newton-type iteration and establish convergence and convergence…

Numerical Analysis · Mathematics 2015-04-01 Fabian Dunker , Jean-Pierre Florens , Thorsten Hohage , Jan Johannes , Enno Mammen

Self-mode-locking has become an emerging path to the generation of ultrashort pulses with vertical-external-cavity surface-emitting lasers. In our work, a strong Kerr nonlinearity that is so far assumed to give rise to mode-locked operation…

Compressible electron flow through a narrow cavity is theoretically unstable, and the oscillations occurring during the instability have been proposed as a method of generating Terahertz radiation. We numerically demonstrate that the…

Mesoscale and Nanoscale Physics · Physics 2021-01-08 Christian B. Mendl , Marco Polini , Andrew Lucas

We derive the current response of noncentrosymmetric metal in normal and in superconducting states to the electromagnetic field with finite frequency and wave vector. The conductivity tensor is found contains the linear in wave vector off…

Strongly Correlated Electrons · Physics 2009-03-20 V. P. Mineev , Yu Yoshioka

Nonlinear Kronig-Penney model has been frequently employed to study transmission problem of electron wave in a nonlinear electrified chain or in a doped semiconductor superlattice. Here from an integral equation we derive a novel exact…

Quantum Physics · Physics 2016-02-17 Chao Kong , Kuo Hai , Jintao Tan , Hao Chen , Wenhua Hai

The paper is a follow-up of the recently introduced kernel-based framework to identify nonlinear input-output systems regularized by desirable input-output incremental properties. Assuming that the system has fading memory, we propose to…

Systems and Control · Electrical Eng. & Systems 2025-11-14 Yongkang Huo , Thomas Chaffey , Rodolphe Sepulchre

Coherent continuous wave (CW) terahertz spectroscopy is an extremely valuable technique that allows for the interrogation of systems that exhibit narrow resonances in the terahertz (THz) frequency range, such as high-quality (high-Q) THz…

Optics · Physics 2019-05-01 Dominik Walter Vogt , Miro Erkintalo , Rainer Leonhardt

Nonlinear optics has become the workhorse for countless applications in classical and quantum optics, from optical bistability to single photon pair generation. However, the intrinsic weakness of optical nonlinearity has meant that large…

Using a super-operator formulation of linearized time-dependent density-functional theory, the dynamical polarizability of a system of interacting electrons is given a matrix continued-fraction representation whose coefficients can be…

Materials Science · Physics 2009-11-11 B. Walker , A. M. Saitta , R. Gebauer , S. Baroni

Nonlinear frequency combs, including electro-optic and Kerr combs, have become central platforms for chip-scale frequency synthesis. Recent breakthroughs in strong-coupling electro-optic modulation further expanded their accessible…

We propose theoretically a method for the control of the frequency of the nonlinear optical response of a model nonlinear medium driven by an electric field and suggest an experimental realization on the basis of isotropic LiF, or NaCl…

Optics · Physics 2013-09-18 L. Chotorlishvili , A. Sukhov , S. Wimberger , J. Berakdar

A theory of nonlinear signal propagation in multi-span wavelength division multiplexed coherent transmission systems that employ the semiconductor optical amplifier as in-line amplifiers is presented for the first time. The rigorous…

Optics · Physics 2017-11-17 Amirhossein Ghazisaeidi

We have observed optical birefringence in liquids induced by single-cycle THz pulses with field strengths exceeding 100 kV/cm. The induced change in polarization is proportional to the square of the THz electric field. The time-dependent…

Other Condensed Matter · Physics 2015-05-13 Matthias C. Hoffmann , Nathaniel C. Brandt , Harold Y. Hwang , Ka-Lo Yeh , Keith A. Nelson

We investigate the effect of phenomenological relaxation parameters on the third order optical nonlinearity of doped graphene by perturbatively solving the semiconductor Bloch equation around the Dirac points. An analytic expression for the…

Materials Science · Physics 2015-12-24 J. L. Cheng , N. Vermeulen , J. E. Sipe

We report a novel experimental technique to investigate ultrafast dynamics in photoexcited molecules by probing the third-order nonlinear optical susceptibility. A non-colinear 3-pulse scheme is developed to probe the ultrafast dynamics of…

The non-linear response of infinite periodic solids to homogenous electric fields and collective atomic displacements is discussed in the framework of density functional perturbation theory. The approach is based on the 2n + 1 theorem…

Materials Science · Physics 2007-05-23 M. Veithen , X. Gonze , Ph. Ghosez

We study the non-linear conductance $\mathcal{G}\sim\partial^2I/\partial V^2|_{V=0}$ in coherent quasi-1D weakly disordered metallic wires. The analysis is based on the calculation of two fundamental correlators (correlations of…

Mesoscale and Nanoscale Physics · Physics 2018-02-22 Christophe Texier , Johannes Mitscherling

We propose non-stationary spectral kernels for Gaussian process regression. We propose to model the spectral density of a non-stationary kernel function as a mixture of input-dependent Gaussian process frequency density surfaces. We solve…

Machine Learning · Statistics 2019-09-25 Sami Remes , Markus Heinonen , Samuel Kaski