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A laser pulse composed of a fundamental and an appropriately phased second harmonic can drive a time-dependent current of photoionized electrons that generates broadband THz radiation. Over the propagation distances relevant to many…

We investigate disorder effects on Landau levels in Dirac electron systems with the use of a non-Hermitian quasiparticle Hamiltonian formalism. This formalism reveals that spin-dependent scattering rates induce the spectrum collapse of…

Mesoscale and Nanoscale Physics · Physics 2021-06-07 Taiki Matsushita , Yuki Nagai , Satoshi Fujimoto

High-field terahertz (THz) pulse generation is investigated through the interaction of an intense single-color CO2 laser pulse with helium (He) gas targets. Employing multi-dimensional Particle-In-Cell (PIC) simulations, this study reveals…

Plasma Physics · Physics 2024-05-22 Srimanta Maity , Garima Arora

Exciton-polaritons in semiconductors are quasi-particles which have recently shown the capability to undergo phase transition into a coherent hybrid state of light and matter. The observation of such quasi-particles in organic microcavities…

Polarisation analysis of synchrotron THz radiation was carried out with a standard stretched polyethylene polariser and revealed that the linearly polarised (horizontal) component contributes up to 22 +/- 5% to the circular polarised…

Spintronic emitters promise to revolutionise terahertz (THz) sources by converting ultrafast optical pulses into broadband THz radiation without phase-matching constraints. Because the conversion relies on spin-current injection across a…

Terahertz pulse generation by ultra-intense two-color laser fields ionizing gases with near- to far-infrared carrier wavelength is studied from particle-in-cell (PIC) simulations. For long wavelength ($10.6\ \mu$m) promoting a large ratio…

Plasma Physics · Physics 2020-01-01 J. Déchard , X. Davoine , L. Bergé

Excitons, composite electron-hole quasiparticles, are known to play an important role in optoelectronic phenomena in many semiconducting materials. Recent experiments and theory indicate that the band-gap optics of the newly discovered…

Mesoscale and Nanoscale Physics · Physics 2015-09-02 Yuri N. Gartstein , Xiao Li , Chuanwei Zhang

Monolayers of transition metal dichalcogenides (TMDCs), known for their strong excitonic states with high binding energies in the visible spectrum at room temperature, offer great potential for polariton-driven devices. While polariton…

Dark excitons in transition metal dichalcogenides (TMD) have been so far neglected in the context of polariton physics due to their lack of oscillator strength. However, in tungsten-based TMDs, dark excitons are known to be the…

Adding a small subdominant quadratic in momentum term to a dominant linear Dirac dispersion curve affects conduction and valence band differently and leads to an hourglass-like structure for energy as a function of momentum. This applies to…

Mesoscale and Nanoscale Physics · Physics 2013-07-09 Zhou Li , J. P. Carbotte

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 demonstrate experimentally that in an asymmetric quantum well in presence of quantizing magnetic field tilted in XZ plane, confining potential V(z) lifts Landau level degeneracy related to position of the centers of electron cyclotron…

Mesoscale and Nanoscale Physics · Physics 2010-04-14 S. A. Emelyanov

We investigate Dirac fermions on the surface of the topological insulator Bi2Se3 using scanning tunneling spectroscopy. Landau levels (LLs) are observed in the tunneling spectra in a magnetic field. In contrast to LLs of conventional…

Mesoscale and Nanoscale Physics · Physics 2010-08-12 T. Hanaguri , K. Igarashi , M. Kawamura , H. Takagi , T. Sasagawa

Polariton lasing is demonstrated on the zero dimensional states of single GaAs/GaAlAs micropillar cavities. Under non resonant excitation, the measured polariton ground state occupancy is found to be as large as $10^{4}$. Changing the…

Using a model methane-like chiral system, we theoretically demonstrate a possibility to access photoelectron circular dichroism (PECD) by a single experiment with two overlapping laser pulses of carrier frequencies $\omega$ and $2\omega$,…

Atomic and Molecular Clusters · Physics 2018-12-20 Philipp V. Demekhin , Anton N. Artemyev , Alexander Kastner , Thomas Baumert

We propose a method based on the slice energy spread modulation to generate strong subpicoseond density bunching in high-intensity relativistic electron beams. A laser pulse with periodic intensity envelope is used to modulate the slice…

Accelerator Physics · Physics 2017-05-24 Zhen Zhang , Lixin Yan , Yingchao Du , Wenhui Huang , Chuanxiang Tang , Zhirong Huang

Polarization control of terahertz wave is a challenging subject in terahertz science and technology. Here, we report a simple method to control polarization state of the terahertz wave in terahertz generation process. At room temperature,…

Materials Science · Physics 2015-10-28 R. Takeda , N. Kida , M. Sotome , H. Okamoto

Topological insulators (TIs) are characterized by possessing metallic (gapless) surface states and a finite band-gap state in the bulk. As the thickness of a TI layer decreases down to a few nanometer, hybridization between the top and…

A terahertz metamaterial consisting of radiative slot antennas and subradiant complementary split-ring resonators exhibits plasmon induced opacity in a narrow spectral range due to the destructive interference between the bright and dark…