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There are implementations and proposals for using microwave or optical radiation for electron acceleration, undulation, deflection, and spatial as well as temporal focusing. Using terahertz (THz) radiation in such applications can be…

Accelerator Physics · Physics 2011-10-03 J. Hebling , J. A. Fülöp , M. I. Mechler , L. Pálfalvi , C. Tőke , G. Almási

We optically excite $^{85}$Rb atoms in a heated vapor cell to a low-lying Rydberg state 10D$_{5/2}$ and observe directional terahertz (THz) beams at 3.3 THz and 7.8 THz. These THz fields are generated by amplified spontaneous emission from…

Atomic Physics · Physics 2021-03-10 Mark Lam , Sambit B. Pal , Thibault Vogt , Martin Kiffner , Wenhui Li

We propose a novel scheme to generate single-cycle terahertz (THz) pulses via reflection of an optical femtosecond pulse train from a thin layer of nonlinear resonant medium. Our method is based on a coherent control of low-frequency…

A novel method is presented for generating radiation using the beat wave associated with a bi-frequency laser pulse, to excite plasma oscillations in a plasma slab with a density gradient. By resonantly exciting a plasma wave, it can be…

Polarization is one of the basic properties of electromagnetic waves conveying valuable information in signal transmission and sensitive measurements. Conventional methods for advanced polarization control impose demanding requirements on…

We present a temporally-multiplexed dual-colour terahertz (THz) imaging technique using THz-to-optical conversion in atomic vapour. By rapidly alternating the pump laser frequency, we sequentially excite two atomic states, each absorbing a…

Atomic Physics · Physics 2025-07-16 Lucy A. Downes , C. Stuart Adams , Kevin J. Weatherill

We study THz-emission from a plasma driven by an incommensurate-frequency two-colour laser field. A semi-classical transient electron current model is derived from a fully quantum-mechanical description of the emission process in terms of…

A highly efficient, practical approach to high-energy terahertz (THz) generation based on spectrally cascaded optical parametric amplification (THz-COPA) is introduced. The THz wave initially generated by difference frequency generation…

We directly observe longitudinal electromagnetic fields in focused freely propagating terahertz beams of radial and linear polarization. In accordance with theory, the longitudinal fields are phase shifted by a value of pi/2 with respect to…

Optics · Physics 2015-06-11 S. Winnerl , R. Hubrich , M. Mittendorff , H. Schneider , M. Helm

In Terahertz (THz) technology, one of the long-standing challenges has been the formation of intense pulses covering the hard-to-access frequency range of 1-15 THz (so-called THz gap). This frequency band, lying between the electronically…

Optics · Physics 2014-07-29 C. Vicario , B. Monoszlai , M. Jazbinsek , S. -H Lee , O. -P. Kwon , C. P. Hauri

For facile manipulation of polarization states of light for applications in communications, imaging, and information processing, an efficient mechanism is desired for rotating light polarization with a minimum interaction length. Here, we…

Photon pairs, highly entangled in polarization have been generated under femtosecond laser pulse excitation by a type I crystal source, operating in a single arm interferometric scheme. The relevant effects of temporal walk-off existing in…

Quantum Physics · Physics 2009-11-13 M. Barbieri , C. Cinelli , F. De Martini , P. Mataloni

Properties of circularly polarized waves are studied in the pulsar magnetosphere plasma. It is shown that some observational characteristics of the circular polarization observed in the pulsar radio emission can be qualitatively explained…

Astrophysics · Physics 2009-11-13 G. Gogoberidze , G. Z. Machabeli

We show that planar semiconductor microcavities in the strong coupling regime can be used as sources of stimulated terahertz (THz) radiation. Emitted THz photons would have a frequency of the spliting of the cavity polariton modes. The…

Mesoscale and Nanoscale Physics · Physics 2010-11-23 K. V. Kavokin , M. A. Kaliteevski , R. A. Abram , A. V. Kavokin , S. Sharkova , I. A. Shelykh

We analytically show how a superposition of beamlets produces terahertz radiation with greater spatial homogeneity and efficiency compared to tilted-pulse-fronts generated by diffraction gratings. The advantages are particularly notable for…

We study the higher-harmonic generation (HHG) using elliptically polarized two-color driving fields. The HHG via bi-chromatic counter-rotating laser fields is a promising source of circularly polarized ultrashort XUV radiation at the…

Atomic Physics · Physics 2022-01-12 Rambabu Rajpoot , Amol R. Holkundkar , Jayendra N. Bandyopadhyay

A relativistic electron-positron beam propagating through a magnetized electron-ion plasma is shown to generate both circularly and linearly polarized synchrotron radiation. The degrees of circular and linear polarizations depend both on…

Plasma Physics · Physics 2019-05-29 Ujjwal Sinha , Christoph H. Keitel , Naveen Kumar

The coherent radiation spectrum of two-level polar molecules with UV transition is studied at the multiphoton resonant excitation by a moderately strong laser field. The spectrum corresponding to harmonic generation and low-frequency…

Atomic Physics · Physics 2011-06-14 H. K. Avetissian , B. R. Avchyan , G. F. Mkrtchian

We theoretically investigate the ultrafast terahertz(THz) properties of monolayer graphene. The analytical formulations of the photon carrier, electric polarization and optical current are obtained by solving the Bloch-equations in present…

Mesoscale and Nanoscale Physics · Physics 2016-06-23 Q. Jin , H. M. Dong , K. Han , X. F. Wang

We demonstrate photoacoustic wave propagation with a plane wavefront in liquid water using a terahertz (THz) laser pulse. The THz light can effectively generate the photoacoustic wave in water because of strong absorption via a stretching…

Optics · Physics 2020-08-20 Masaaki Tsubouchi , Hiromichi Hoshina , Masaya Nagai , Goro Isoyama