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Ultrafast photocurrent measurements are performed on individual carbon nanotube PN junction photodiodes. The photocurrent response to sub-picosecond pulses separated by a variable time delay {\Delta}t shows strong photocurrent suppression…

Mesoscale and Nanoscale Physics · Physics 2015-05-30 Nathaniel M. Gabor , Zhaohui Zhong , Ken Bosnick , Paul L. McEuen

Over the last few years, tremendous progress has been gained in the generation and application of ultrashort radiation pulses. Recently, free-electron lasers generating ultrashort pulses with high peak power from the extreme ultraviolet…

Accelerator Physics · Physics 2023-06-21 Najmeh Mirian

We report an all-polarization-maintaining fiber optic approach to generating sub-2 cycle pulses at 2 {\mu}m and a corresponding octave-spanning optical frequency comb. Our configuration leverages mature Er:fiber laser technology at 1.5…

When a fs duration and hundreds of kA peak current electron beam traverses the vacuum and high-density plasma interface a new process, that we call relativistic transition radiation (R-TR) generates an intense $\sim100$ as pulse containing…

Recent initiatives in ultra-short, GeV electron beam generation have focused on achieving sub-fs pulses for driving X-ray free-electron lasers (FELs) in single-spike mode. This scheme employs very low charge beams, which may allow existing…

We report the first demonstration to our knowledge of a continuously tunable picosecond laser operating around 1 MHz. The emission can be tuned from 640 to 685 nm and the repetition rate from 200 kHz to 1 MHz with a pulse duration of less…

An accelerator beam can generate low energy electrons in the beam-pipe, generally called electron cloud, that can produce instabilities in a positively charged beam. One method of measuring the electron cloud density is by coupling…

Using a 3D fully-vectorial nonlinear time-domain analysis we numerically investigate the generation of terahertz radiation by pumping a photonic crystal microcavity out of resonance. High quality factors and a quadratic susceptibility lead…

Optics · Physics 2009-11-11 Andrea Di Falco , Claudio Conti , Gaetano Assanto

We demonstrate that an ultrashort high intensity laser pulse can propagate for hundreds of Rayleigh ranges in a prepared neutral hydrogen channel by generating its own plasma waveguide as it propagates; the front of the pulse generates a…

Plasma Physics · Physics 2020-11-11 L. Feder , B. Miao , J. E. Shrock , A. Goffin , H. M. Milchberg

Autoresonance laser acceleration of electrons is theoretically investigated using circularly polarized focused Gaussian pulses. Many-particle simulations demonstrate feasibility of creating over 10-GeV electron bunches of ultra-high quality…

Accelerator Physics · Physics 2015-06-16 Benjamin J. Galow , Jian-Xing Li , Yousef I. Salamin , Zoltán Harman , Christoph H. Keitel

Since the era of the Fermi/LAT and atmospheric Cerenkov telescopes, pulsars are known to emit high and very high-energy photons, in the MeV-GeV range and sometimes up to TeV. To date, it is still unclear where and how these photons are…

High Energy Astrophysical Phenomena · Physics 2019-02-13 Jérôme Pétri

A laser-boosted relativistic solid-density paraboloidal foil is known to efficiently reflect and focus a counterpropagating laser pulse. Here we show that in the case of an ultrarelativistic counterpropagating pulse, a high-energy and…

Plasma Physics · Physics 2014-07-14 M. Tamburini , A. Di Piazza , T. V. Liseykina , C. H. Keitel

Radiofrequency (RF) electron guns operating at high accelerating gradients offer a pathway to producing bright electron bunches. Such beams are expected to revolutionize many areas of science: they could form the backbone of next-generation…

Generation of collimated, quasi-monoenergetic electron beams (peak energy ~17-22MeV, divergence ~10mrad, energy spread ~20%) by interaction of Ti:sapphire laser pulse of 200fs duration, focussed to an intensity of ~ 2.1x10^18 W/cm^2,with an…

Plasma Physics · Physics 2019-08-09 D. Hazra , A. Moorti , B. S. Rao , A. Upadhyay , J. A. Chakera , P. A. Naik

We propose a novel scheme for frequency-tunable sub-cycle electromagnetic pulse generation. To this end a pump electron beam is injected into an electromagnetic seed pulse as the latter is reflected by a mirror. The electron beam is shown…

Plasma Physics · Physics 2019-03-27 Illia Thiele , Evangelos Siminos , Tünde Fülöp

This paper discusses numerical and experimental results on frequency downshifting and upshifting of a 10 $\mu$m infrared laser to cover the entire wavelength (frequency) range from $\lambda$=1-150 $\mu$m ($\nu$=300-2 THz) using two…

Plasma Physics · Physics 2021-02-24 Zan Nie , Yipeng Wu , Chaojie Zhang , Warren B. Mori , Chan Joshi , Wei Lu , Chih-Hao Pai , Jianfei Hua , Jyhpyng Wang

Coherent control over electron dynamics in atoms and molecules using high-intensity circularly-polarized laser pulses gives rise to current loops, resulting in the emission of magnetic fields. We propose and demonstrate with ab-initio…

Traditionally one defines the speed of a wave as a property of the medium. Recent studies in photonics have challenged this idea, indicating that spatial shaping of the optical wavefront has can alter the arrival time of single photons when…

We demonstrated for the first time the production of highly polarized short-pulse positrons with a finite energy spread in accordance with a new scheme that consists of two-quantum processes, such as inverse Compton scatterings and…

High Energy Physics - Experiment · Physics 2009-11-11 T. Omori , M. Fukuda , T. Hirose , Y. Kurihara , R. Kuroda , M. Nomura , A. Ohashi , T. Okugi , K. Sakaue , T. Saito , J. Urakawa , M. Washio , I. Yamazaki