scholarly journals Coherent short wavelength radiation via picosecond Nd:glass lasers

2002 ◽  
Vol 20 (1) ◽  
pp. 59-65 ◽  
Author(s):  
H. KURODA ◽  
T. OZAKI ◽  
A. ISHIZAWA ◽  
T. KANAI ◽  
K. YAMAMOTO ◽  
...  
Keyword(s):  
Harmonic Generation ◽  
Laser System ◽  
High Harmonic ◽  
X Rays ◽  
X Ray ◽  
Particle In Cell ◽  
Cell Simulation ◽  
Wavelength Radiation ◽  
Hydrodynamic Code ◽  
Scale Length

The generation of coherent soft X rays is studied using a terawatt picosecond Nd:glass laser system. Two different methods are investigated as candidates for efficient generation of such radiation, namely, longitudinally pumped transient collisional excitation nickel-like molybdenum X-ray laser, and high-harmonic generation from solid–vacuum interfaces. In the course of experiments on longitudinally pumped X-ray lasers, unexpected jetlike structures are observed in the visible emission of the molybdenum plasma, extending over a length of several millimeters. An interesting characteristic of this phenomena is that clear jets are observed only for longitudinal pump intensities between 5 × 1014 and 7 × 1014 W/cm2. The effects of a finite scale length density gradient on surface harmonics is also investigated. The efficiency of harmonic generation from near-solid density plasma is found to increase by a factor of 2 to 3 when using prepulses. The scale length of the preplasma is simulated using a one-dimensional hydrodynamic code, and the increase in efficiency is verified to be in accordance with particle-in-cell simulation results.

scholarly journals Transient absorption spectroscopy using high harmonic generation: a review of ultrafast X-ray dynamics in molecules and solids

2019 ◽  
Vol 377 (2145) ◽  
pp. 20170463 ◽  
Author(s):  
Romain Geneaux ◽  
Hugo J. B. Marroux ◽  
Alexander Guggenmos ◽  
Daniel M. Neumark ◽  
Stephen R. Leone
Keyword(s):  
Time Scales ◽  
Harmonic Generation ◽  
Absorption Spectroscopy ◽  
Transient Absorption ◽  
High Harmonic ◽  
High Harmonic Generation ◽  
Transient Absorption Spectroscopy ◽  
Spectroscopic Techniques ◽  
X Rays ◽  
X Ray

Attosecond science opened the door to observing nuclear and electronic dynamics in real time and has begun to expand beyond its traditional grounds. Among several spectroscopic techniques, X-ray transient absorption spectroscopy has become key in understanding matter on ultrafast time scales. In this review, we illustrate the capabilities of this unique tool through a number of iconic experiments. We outline how coherent broadband X-ray radiation, emitted in high-harmonic generation, can be used to follow dynamics in increasingly complex systems. Experiments performed in both molecules and solids are discussed at length, on time scales ranging from attoseconds to picoseconds, and in perturbative or strong-field excitation regimes. This article is part of the theme issue ‘Measurement of ultrafast electronic and structural dynamics with X-rays’.

scholarly journals Attosecond soft X-ray high harmonic generation

2019 ◽  
Vol 377 (2145) ◽  
pp. 20170468 ◽  
Author(s):  
Allan S. Johnson ◽  
Timur Avni ◽  
Esben W. Larsen ◽  
Dane R. Austin ◽  
Jon P. Marangos
Keyword(s):  
Harmonic Generation ◽  
Spectral Range ◽  
High Harmonic ◽  
High Harmonic Generation ◽  
Intense Laser ◽  
X Rays ◽  
X Ray ◽  
Optical Phenomenon ◽  
Highly Nonlinear ◽  
Attosecond Pulses

High harmonic generation (HHG) of an intense laser pulse is a highly nonlinear optical phenomenon that provides the only proven source of tabletop attosecond pulses, and it is the key technology in attosecond science. Recent developments in high-intensity infrared lasers have extended HHG beyond its traditional domain of the XUV spectral range (10–150 eV) into the soft X-ray regime (150 eV to 3 keV), allowing the compactness, stability and sub-femtosecond duration of HHG to be combined with the atomic site specificity and electronic/structural sensitivity of X-ray spectroscopy. HHG in the soft X-ray spectral region has significant differences from HHG in the XUV, which necessitate new approaches to generating and characterizing attosecond pulses. Here, we examine the challenges and opportunities of soft X-ray HHG, and we use simulations to examine the optimal generating conditions for the development of high-flux, attosecond-duration pulses in the soft X-ray spectral range. This article is part of the theme issue ‘Measurement of ultrafast electronic and structural dynamics with X-rays’.

3D Electromagnetic Particle-in-Cell Simulation of EMP Generated by Pulsed X-rays

2021 ◽  
Vol 35 (11) ◽  
pp. 1400-1401
Author(s):  
Zhiqian Xu ◽  
Cui Meng
Keyword(s):  
Field Strength ◽  
Symmetry Axis ◽  
Simulation Method ◽  
X Rays ◽  
Resonant Frequencies ◽  
X Ray ◽  
Particle In Cell ◽  
Cell Simulation ◽  
Cavity System ◽  
Peak Value

Pulsed X-rays could cause significant cavity system-generated electromagnetic pulse (SGEMP) interference. A 3D electromagnetic particle-in-cell simulation approach is developed to calculate EMP generated inside a cylindrical cavity after X-ray illumination. The waveform, spatial distributions and resonant frequencies of cavity SGEMP are demonstrated by the computations. The peak value of cavity SGEMP main pulse is 72.88 kV/m. When farther away from the charge emitting face, the field strength decreases quickly and its polarity reverses; when the distance from symmetry axis increases, the field strength declines relatively slower. The cavity SGEMP would form a stable resonance and its frequency is dominated by the radius and length of cavity. The simulation method is verified and can be applied to the X-ray radiation hardness.

scholarly journals Bright High-Order Harmonic Generation around 30 nm Using Hundred-Terawatt-Level Laser System for Seeding Full Coherent XFEL

2018 ◽  
Vol 8 (9) ◽  
pp. 1446 ◽  
Author(s):  
Luyao Zhang ◽  
Yinghui Zheng ◽  
Guicun Li ◽  
Zhengmao Jia ◽  
Yanyan Li ◽  
...  
Keyword(s):  
Harmonic Generation ◽  
Beam Quality ◽  
Laser System ◽  
High Harmonic ◽  
High Order ◽  
Laser Source ◽  
High Order Harmonic Generation ◽  
X Ray ◽  
High Order Harmonic ◽  
Level Laser

In the past few years, the laser wakefield acceleration (LWFA) electron is a hot topic. One of its applications is to produce soft X-ray free-electron laser (XFEL). During this process, high harmonic generation (HHG) is a potential seed. To decrease the timing jitter between LWFA and HHG, it is better for them to come from the same laser source. We have experimentally investigated bright high-order harmonic generation with a 200-terawatt (TW)/1-Hz Ti: Sapphire laser system. By using the loosely focused method and optimizing the phase-matching conditions, we have obtained bright high-order harmonics around 30 nm. Output energy of the 29th harmonic (27.6 nm) reaches as high as 100 nJ per pulse, and the harmonic beam divergence is estimated to be 0.3 mrad in a full width at half maximum (FWHM). Although the hundred-TW-level laser system has the problems of poor beam quality and shot-to-shot energy fluctuation for HHG, the generated soft X-ray (~30 nm) sources can also have good stability by carefully optimizing the laser system.

scholarly journals Few-Cycle Infrared Pulse Evolving in FEL Oscillators and Its Application to High-Harmonic Generation for Attosecond Ultraviolet and X-ray Pulses

Atoms ◽  
2021 ◽  
Vol 9 (1) ◽  
pp. 15
Author(s):  
Ryoichi Hajima
Keyword(s):  
Harmonic Generation ◽  
Short Pulse ◽  
High Harmonic ◽  
High Harmonic Generation ◽  
Pulse Generation ◽  
Solid State Lasers ◽  
Linear Accelerators ◽  
X Ray ◽  
Ultrafast Science ◽  
Historical Remarks

Generation of few-cycle optical pulses in free-electron laser (FEL) oscillators has been experimentally demonstrated in FEL facilities based on normal-conducting and superconducting linear accelerators. Analytical and numerical studies have revealed that the few-cycle FEL lasing can be explained in the frame of superradiance, cooperative emission from self-bunched systems. In the present paper, we review historical remarks of superradiance FEL experiments in short-pulse FEL oscillators with emphasis on the few-cycle pulse generation and discuss the application of the few-cycle FEL pulses to the scheme of FEL-HHG, utilization of infrared FEL pulses to drive high-harmonic generation (HHG) from gas and solid targets. The FEL-HHG enables one to explore ultrafast science with attosecond ultraviolet and X-ray pulses with a MHz repetition rate, which is difficult with HHG driven by solid-state lasers. A research program has been launched to develop technologies for the FEL-HHG and to conduct a proof-of-concept experiment of FEL-HHG.

scholarly journals Table-top extreme ultraviolet second harmonic generation

2021 ◽  
Vol 7 (21) ◽  
pp. eabe2265
Author(s):  
Tobias Helk ◽  
Emma Berger ◽  
Sasawat Jamnuch ◽  
Lars Hoffmann ◽  
Adeline Kabacinski ◽  
...  
Keyword(s):  
Second Harmonic Generation ◽  
Harmonic Generation ◽  
First Principles ◽  
Extreme Ultraviolet ◽  
Second Harmonic ◽  
High Harmonic ◽  
Electronic Structure Calculations ◽  
Free Electron Lasers ◽  
X Ray ◽  
Structure Calculations

The lack of available table-top extreme ultraviolet (XUV) sources with high enough fluxes and coherence properties has limited the availability of nonlinear XUV and x-ray spectroscopies to free-electron lasers (FELs). Here, we demonstrate second harmonic generation (SHG) on a table-top XUV source by observing SHG near the Ti M2,3 edge with a high-harmonic seeded soft x-ray laser. Furthermore, this experiment represents the first SHG experiment in the XUV. First-principles electronic structure calculations suggest the surface specificity and separate the observed signal into its resonant and nonresonant contributions. The realization of XUV-SHG on a table-top source opens up more accessible opportunities for the study of element-specific dynamics in multicomponent systems where surface, interfacial, and bulk-phase asymmetries play a driving role.

scholarly journals Particle-in-cell simulation of x-ray wakefield acceleration and betatron radiation in nanotubes

2016 ◽  
Vol 19 (10) ◽  
Author(s):  
Xiaomei Zhang ◽  
Toshiki Tajima ◽  
Deano Farinella ◽  
Youngmin Shin ◽  
Gerard Mourou ◽  
...  
Keyword(s):  
X Ray ◽  
Particle In Cell ◽  
Wakefield Acceleration ◽  
Cell Simulation

scholarly journals High Repetition Rate and Coherent Free-Electron Laser in the X-Rays Range Tailored for Linear Spectroscopy

Instruments ◽  
2019 ◽  
Vol 3 (3) ◽  
pp. 47 ◽  
Author(s):  
Vittoria Petrillo ◽  
Michele Opromolla ◽  
Alberto Bacci ◽  
Illya Drebot ◽  
Giacomo Ghiringhelli ◽  
...  
Keyword(s):  
Free Electron ◽  
Repetition Rate ◽  
Free Electron Laser ◽  
Extreme Ultraviolet ◽  
High Harmonic ◽  
High Repetition Rate ◽  
X Rays ◽  
Regenerative Amplifier ◽  
X Ray ◽  
High Repetition

Fine time-resolved analysis of matter—i.e., spectroscopy and photon scattering—in the linear response regime requires fs-scale pulsed, high repetition rate, fully coherent X-ray sources. A seeded Free Electron Laser (FEL) driven by a Linac based on Super Conducting cavities, generating 10 8 – 10 10 coherent photons at 2–5 keV with 0.2–1 MHz of repetition rate, can address this need. Three different seeding schemes, reaching the X-ray range, are described hereafter. The first two are multi-stage cascades upshifting the radiation frequency by a factor of 10–30 starting from a seed represented by a coherent flash of extreme ultraviolet light. This radiation can be provided either by the High Harmonic Generation of an optical laser or by an FEL Oscillator operating at 12–14 nm. The third scheme is a regenerative amplifier working with X-ray mirrors. The whole chain of the X-ray generation is here described by means of start-to-end simulations.

scholarly journals Possible X-Ray Flares in a Recurrent Nova

1990 ◽  
Vol 122 ◽  
pp. 427-428
Author(s):  
Izumi Hachisu ◽  
Hiroshi Itoh
Keyword(s):  
Dynamical Evolution ◽  
Spectral Shape ◽  
Spherically Symmetric ◽  
X Rays ◽  
X Ray ◽  
Wind Region ◽  
Recurrent Nova ◽  
Red Giant ◽  
Hydrodynamic Code

Abstract:The dynamical evolution and nonequilibrium X-ray emission of recurrent nova remnants have been investigated by using a spherically symmetric hydrodynamic code. We assume that the nova ejecta expand into a wind from a red-giant companion. The wind material is blast-shocked, and emits copious X-rays. The blast shock soon breaks out of the wind region and the X-ray emission declines drastically. The blast shock eventually catches up with the relatively slow ejecta of the previous outbursts. The X-ray emission may then be rejuvenated in both luminosity and spectral shape.

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