scholarly journals Towards GW-Scale Isolated Attosecond Pulse Far beyond Carbon K-Edge Driven by Mid-Infrared Waveform Synthesizer

2018 ◽  
Vol 8 (12) ◽  
pp. 2451 ◽  
Author(s):  
Yuxi Fu ◽  
Hua Yuan ◽  
Katsumi Midorikawa ◽  
Pengfei Lan ◽  
Eiji Takahashi
Keyword(s):  
Single Cycle ◽  
High Order Harmonic Generation ◽  
Mid Infrared ◽  
X Ray ◽  
Water Window ◽  
High Order Harmonic ◽  
Optical Parametric ◽  
Isolated Attosecond Pulse ◽  
Window Region ◽  
The Continuum

We discuss the efficient generation of intense “water window” (0.28–0.54 keV) isolated attosecond pulses (IAPs) using a mid-infrared (MIR) waveform synthesizer. Our numerical simulations clearly indicate that not only a longer-wavelength driving laser but also a weak control pulse in the waveform synthesizer helps extend the continuum cutoff region and reduce the temporal chirp of IAPs in high-order harmonic generation (HHG). This insight indicates that a single-cycle laser field is not an optimum waveform for generating the shortest IAP from the veiwpoints of reducing the attochirp and increasing the efficiency of HHG. By combining a waveform synthesizer technology and a 100 mJ MIR femtosecond pulse based on a dual-chirped optical parametric amplification (DC-OPA) method, a gigawatt-scale IAP (55 as with 10 nJ order) in the water window region can be generated even without attochirp compensation. The MIR waveform synthesizer is highly beneficial for generating a shorter IAP duration in the soft X-ray region because there are no suitable transparent dispersive materials that can be used for compressing the attochirp.

Coherent Water Window X Ray by Phase-Matched High-Order Harmonic Generation in Neutral Media

2008 ◽  
Vol 101 (25) ◽  
Author(s):  
Eiji J. Takahashi ◽  
Tsuneto Kanai ◽  
Kenichi L. Ishikawa ◽  
Yasuo Nabekawa ◽  
Katsumi Midorikawa
Keyword(s):  
Harmonic Generation ◽  
High Order ◽  
High Order Harmonic Generation ◽  
X Ray ◽  
Water Window ◽  
High Order Harmonic ◽  
Neutral Media

Generation of high-intensity KeV isolated attosecond pulse via multi-color inhomogeneous beams superposition

2019 ◽  
Vol 28 (02) ◽  
pp. 1950011
Author(s):  
Hang Liu ◽  
Henry J. Kapteyn ◽  
Katheryn Liu ◽  
April Y. Feng
Keyword(s):  
High Intensity ◽  
Laser Beams ◽  
Half Cycle ◽  
High Order Harmonic Generation ◽  
Mid Infrared ◽  
High Order Harmonic ◽  
Unipolar Pulse ◽  
Resonance Enhancement ◽  
Isolated Attosecond Pulse ◽  
Positive Half

A potential scheme to obtain the high-intensity KeV isolated attosecond pulses (IAPs) from the high-order harmonic generation (HHG) has been proposed and studied via the superposition of the multi-color inhomogeneous laser beams. The scheme can be separated into three steps. Firstly, with the superposition of two-color mid-infrared field and a few-cycle infrared field at the proper delay time and the carrier envelope phase, the optimal HHG spectrum can be found. Secondly, with the help of the positive inhomogeneous effect in space, the harmonic emission peaks (HEPs) from the positive half-cycle can be well selected. Secondly, by properly adding a unipolar pulse with the positive peak, the harmonic cutoff can be extended to the KeV region and the harmonic plateau is only contributed by the single HEP. Thirdly, with the introduction of the UV pulse, the signal of the harmonic plateau can be enhanced by at least 500 dB due to the UV-resonance-enhancement-ionization. Finally, through the Fourier transformation of some selected harmonics, the sub-35 as IAPs in the KeV region can be obtained.

Generation of a coherent x ray in the water window region at 1 kHz repetition rate using a mid-infrared pump source

2009 ◽  
Vol 34 (11) ◽  
pp. 1747 ◽  
Author(s):  
Hui Xiong ◽  
Han Xu ◽  
Yuxi Fu ◽  
Jinping Yao ◽  
Bin Zeng ◽  
...  
Keyword(s):  
Repetition Rate ◽  
Mid Infrared ◽  
X Ray ◽  
Water Window ◽  
Pump Source ◽  
Window Region

Improvement of High-Order Harmonic Generation Via Controlling Multiple Acceleration–Recombination Process

2019 ◽  
Vol 74 (7) ◽  
pp. 561-571 ◽  
Author(s):  
Yi Li ◽  
Li-Qiang Feng ◽  
Yan Qiao
Keyword(s):  
Harmonic Generation ◽  
Laser Field ◽  
High Order ◽  
Recombination Process ◽  
Half Cycle ◽  
High Order Harmonic Generation ◽  
Water Window ◽  
High Order Harmonic ◽  
Window Region ◽  
Frequency Chirping

AbstractThe multiple acceleration–recombination process in high-order harmonic generation (HHG) has been investigated and discussed. Generally, the HHG can be explained through the ionization–acceleration–recombination process in each half-cycle waveform of the laser field. In this article, through the waveform control via the two-colour frequency-chirping laser field, the multiple acceleration–recombination process of the free electron in a specific “W” waveform structure can be found, which will lead to the larger emitted photon energies. Moreover, with the optimization of this “W” waveform by changing the frequency chirps, the carrier envelope phases, and the delay time, not only the efficiency of HHG can be enhanced compared with that from the original chirp-free pulse, but also the larger harmonic cutoff can be obtained. Further, with the assistance of the unipolar pulses, the cutoff and the efficiency of HHG can be further improved, showing a water window spectral continuum with the intensity enhancement of 66 times. As a result, by properly superposing some selected harmonics on the spectral continuum, three intense 38-as pulses in the water window region can be obtained.

scholarly journals Mid-Infrared Few-Cycle Pulse Generation and Amplification

Photonics ◽  
2021 ◽  
Vol 8 (8) ◽  
pp. 290
Author(s):  
Kan Tian ◽  
Linzhen He ◽  
Xuemei Yang ◽  
Houkun Liang
Keyword(s):  
Strong Field ◽  
Average Power ◽  
High Energy ◽  
Pulse Generation ◽  
Single Cycle ◽  
Mid Infrared ◽  
Optical Parametric ◽  
Isolated Attosecond Pulse ◽  
Strong Field Physics ◽  
Cycle Pulse

In the past decade, mid-infrared (MIR) few-cycle lasers have attracted remarkable research efforts for their applications in strong-field physics, MIR spectroscopy, and bio-medical research. Here we present a review of MIR few-cycle pulse generation and amplification in the wavelength range spanning from 2 to ~20 μm. In the first section, a brief introduction on the importance of MIR ultrafast lasers and the corresponding methods of MIR few-cycle pulse generation is provided. In the second section, different nonlinear crystals including emerging non-oxide crystals, such as CdSiP2, ZnGeP2, GaSe, LiGaS2, and BaGa4Se7, as well as new periodically poled crystals such as OP-GaAs and OP-GaP are reviewed. Subsequently, in the third section, the various techniques for MIR few-cycle pulse generation and amplification including optical parametric amplification, optical parametric chirped-pulse amplification, and intra-pulse difference-frequency generation with all sorts of designs, pumped by miscellaneous lasers, and with various MIR output specifications in terms of pulse energy, average power, and pulse width are reviewed. In addition, high-energy MIR single-cycle pulses are ideal tools for isolated attosecond pulse generation, electron dynamic investigation, and tunneling ionization harness. Thus, in the fourth section, examples of state-of-the-art work in the field of MIR single-cycle pulse generation are reviewed and discussed. In the last section, prospects for MIR few-cycle lasers in strong-field physics, high-fidelity molecule detection, and cold tissue ablation applications are provided.

Selection and Enhancement of the Single Harmonic Emission Event in the Water Window Region

2018 ◽  
Vol 73 (11) ◽  
pp. 985-994 ◽  
Author(s):  
Hang Liu ◽  
A. Yuanzi Feng
Keyword(s):  
Fourier Transformation ◽  
Half Cycle ◽  
Laser Polarization ◽  
High Order Harmonic Generation ◽  
Harmonic Emission ◽  
Water Window ◽  
Polarization Gating ◽  
High Order Harmonic ◽  
Window Region ◽  
Cycle Pulse

AbstractThe control of the high-order harmonic generation in the half-cycle region has been investigated by using the improved polarization gating (PG) technology. It is found that by properly controlling the delay time of the PG pulse, the contribution of the harmonic plateau is nearly coming from the single harmonic emission event, which is much better for producing the single attosecond pulses (SAPs). Further, by properly adding an ultraviolet pulse and a half-cycle pulse in the driven laser polarization direction, the harmonic yield can be enhanced and the harmonic cutoff can be extended, showing a high-intensity harmonic plateau covering the whole water window region. Finally, through the Fourier transformation of some selected harmonics, a 35 as SAP in the water window region can be obtained.

Generation of water window single attosecond pulse from multi-cycle mid-infrared laser field with chirp gating modulation

2019 ◽  
Vol 33 (06) ◽  
pp. 1950064 ◽  
Author(s):  
Hang Liu ◽  
Henry M. Schafer ◽  
R. L. Q. Feng ◽  
A. Yuanzi Feng
Keyword(s):  
Pulse Duration ◽  
Laser Field ◽  
Initial State ◽  
Mid Infrared ◽  
Water Window ◽  
High Order Harmonic ◽  
Chirp Modulation ◽  
Window Region ◽  
Gating Modulation ◽  
Cycle Pulse

A potential scheme to produce the water window single attosecond pulses (SAPs) from the multi-cycle mid-infrared (MIR) laser field has been investigated with the help of the chirp gating modulation. It is found that with the introduction of the laser chirp (i.e. up-chirp or down-chirp modulation), the extension of the harmonic cutoff can be achieved and the single harmonic radiation peak (HRP) can be selected during the harmonic emission process. Moreover, the chirp gating modulation on the high-order harmonic generation (HHG) is sensitive to the few-cycle pulse duration, but it is not very sensitive to the multi-cycle pulse duration. Moreover, a larger extension of the harmonic cutoff covering the whole water window region can be found with the help of the multi-cycle down-chirp modulation. Further, by properly choosing the coherent superposition of the ground state and the high Rydberg state as the initial state, the efficiency of HHG can be enhanced by 5 orders of magnitude. Finally, a series of high-intensity sub-40as pulses covering the water window region can be obtained.

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