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Near-field spatial intensity profile of the picosecond pulses: (a) before beam shaping device; (b) after beam shaping device.
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We report on a two-arm hybrid high-power laser system (HPLS) able to deliver 2 × 10 PW femtosecond pulses, developed at the Bucharest-Magurele Extreme Light Infrastructure Nuclear Physics (ELI-NP) Facility. A hybrid front-end (FE) based on a Ti:sapphire chirped pulse amplifier and a picosecond optical parametric chirped pulse amplifier based on bet...
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... output regenerative amplifier laser pulses of 2 mJ energy are injected in a beam shaping device which consists of a quartz spherical lens combined with a polarizer. After the beam shaping, 1 mJ energy laser pulses, with a spatial intensity distribution converted from Gaussian to super-Gaussian profile, are generated ( Figure 4). ...
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We report on a two-arm hybrid high-power laser system (HPLS) able to deliver 2 × 10 PW femtosecond pulses, developed at the Bucharest-Magurele Extreme Light Infrastructure Nuclear Physics (ELI-NP) Facility. A hybrid front-end (FE) based on a Ti:sapphire chirped pulse amplifier and a picosecond optical parametric chirped pulse amplifier based on bet...
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... 1 引 言 过去二十多年间，超强超短激光的峰值功率长期徘徊在 1 拍瓦左右(1 拍瓦等于 10 15 瓦 特) [1,2] 。过去五年间，由于激光技术和物理需求的共同发展，超强超短激光的峰值功率快 速提升至超过 4 拍瓦 [3][4][5][6] 和大于 10 拍瓦 [7,8] ，创造了前所未有的极限强度，同时也极大地促 进了强场激光物理的高速发展 [9,10] 。未来面向艾瓦(10 18 瓦特)激光的发展 [11][12][13] 更有可能为 研究诸如强场量子电动力学等极端物理提供先进的实验手段 [14][15][16][17][18][19][20][21] 。近年来，超强超短激光在 帮助强场激光物理不断突破的过程中，其自身也不断面临新的课题，最具代表性的就是时空 耦合效应，或称之为时空耦合畸变 [22][23][24][25][26][27] 。早期的超强超短激光由于光束口径很小，几乎不存 在时空耦合畸变，激光电场的数学表达式可写成时间函数与空间函数的乘积。因此在评价超 强超短激光性能时，比如峰值功率，往往对其时间特性和空间特性分别测量，然后通过计算 获得。这种方法既便捷又合理，从上世纪八十年代后期出现的第一批吉瓦(10 9 瓦特)和太 瓦(10 12 瓦特)激光开始，沿用至九十年代末出现的拍瓦激光，直至本世纪初叶。尽管在超 强超短激光的通用技术中--啁啾脉冲放大(CPA) [28] 和光参量啁啾脉冲放大(OPCPA) [29] --为了引入时间啁啾，展宽器和压缩器中存在一种时空耦合效应，即空间啁啾，但由于色散 元件的对称设计， 这种时空耦合只存在于展宽器和压缩器内部， 在输出端被完美补偿了 [30][31][32][33] [13] 。(a)无畸变；(b)脉冲前沿倾斜；(c)脉冲前沿弯曲。 Fig. 1 Influence of pulse-front distortion on focused pulsed-beam [13] . (a) Without distortion; (b) pulse-front tilt; (c) pulse-front curvature. ...
... (a) Lens induced pulse-front curvature [43] ; (b) Fresnel zone plate induced pulse-front curvature [43] . Fig. 8 We use pulse-front curvature to realize accelerating and decelerating X-shape optical wave-packets [59] . (a) ...
超强超短激光由于在空间上具有大口径、在时间上具有短脉冲，因此极易产生时空耦合效应，例如脉冲前沿畸变，使得脉冲前沿和相位前沿发生时空分离，通常表现为脉冲前沿倾斜或弯曲，不利于获得预期的高聚焦光强。但当这种脉冲前沿畸变（控制）用于产生X形光波包时，却增加了一维全新的自由度，实现了光波包群速度和群加速度的自由控制，可获得超光速、亚光速、加速、减速、甚至动态可控的群速度。通过综述脉冲前沿畸变（控制）在超强超短激光中的不良影响和在X形光波包中的特殊效果，为同一光学现象在不同研究方向间的交叉应用提供些许思考。
... In our case of 0.1-Hz laser operation, direct observation of the target surface for the precise target placement would be more time-consuming than using 10-20 full-power laser shots to find the best focus. The techniques we present in our paper can be used in experiments using laser systems with high repetition rates of 0.1-10 Hz, like ALEPH [48] in Colorado, Astra Gemini [49] in the UK, Apollon [50] in France, ATLAS 3000 and PFS [51] in Munich, BELLA [39] in Berkeley, CoReLS [17] in South Korea, Diocles [52] in Nebraska-Lincoln, DRACO [53] in Dresden, HAPLS [54,55] at ELI-Beamlines in the Czech Republic, HERCULES [4] in Michigan, HF-PW at ELI-ALPS [56] in Hungary, HPLS [19,20] at ELI-NP in Romania, SCAPA [57] at the University of Strathclyde in Glasgow, SULF [31] in China, VEGA [58,59] in Spain, as well as commercial PULSAR laser systems in Canada [60] , Italy [61] and China [62] . ...
... Contemporary high-intensity femtosecond laser facilities that are based on the Chirped Pulse Amplification (CPA) concept [1] now reach subterawatt [2] , multi-terawatt [3][4][5][6][7][8][9][10][11][12] and petawatt [13][14][15][16][17][18][19][20] power levels, with a rapid increase in their number worldwide [21][22][23] . Most of the high-power systems are near-infrared (near-IR) facilities taking advantage of Ti:sapphire lasers, while others operate in the mid-IR [2] or visible [9,10] spectral ranges. ...
... Two 10 PW lasers were successfully developed in China and Europe in 2017 and 2019, respectively. These lasers were constructed at the super-intense ultrafast laser facility (SULF) and the extreme light infrastructure-nuclear physics (ELI-NP) facility [11]. The United States is now engaged in the development of advanced multi-petawatt (PW) lasers, including the zettawatt equivalent ultrashort pulse laser system (ZEUS) [12]. ...
... The super-intense ultrafast laser facility (SULF), located in Shanghai, China, has effectively attained a maximum power output of 10 petawatts. The system demonstrates a pulse duration of 30 femtoseconds, a center wavelength of 800 nanometers, and a repetition frequency of 1 hertz [11]. The European extreme light infrastructure-nuclear physics (ELI-NP) facility has also achieved a peak power of 10 PW with a repetition frequency of 1 Hz and a center wavelength of 800 nanometers [12]. ...
With the development of laser technology, how to improve the output performance and peak power of lasers has become one of the hot directions of current research. This study analyzes the principles and applications of ultra-intensity and ultrashort pulse laser. It firstly outlines the development history of laser technology and the basic definition of ultra-intensity and ultrashort pulse laser. It also mentions the realization methods for generating ultra-intensity and ultrashort pulse lasers, such as mode-locked femtosecond oscillators and CPA-based femtosecond amplifiers. The paper describes the principles of CPA technique and emphasizes its importance in realizing high power ultrashort pulses. The paper discusses various applications of ultra-intensity and ultrashort pulsed laser and summarizes and discusses the major bottlenecks facing current and future ultra-intensity and ultrashort pulsed lasers and their possible solutions. The technical review in this paper aims to enhance the understanding of ultra-intensity and ultrashort pulsed laser and provide insights into the next phase of research exploration in ultra-intensity and ultrashort pulsed lasers.
... The progress of modern high-power laser systems towards generation of extreme fields, currently demonstrating up to 10 PW pulses [1,2] , has been impeded by one main challenge, the modest resistance to laser-induced optical damage of their constituent components. The threshold resistance is further stretched to the limits within the post-compression techniques via thin film compression [3] which have been successfully used to increase the peak power for different input laser pulse duration [4,5] and J-level energy [6] . ...
... The appearance of the incubation effect lowers the LIDT value with the increase in the number of laser pulses. Besides the high cost of the destroyed optical component, catastrophic damage could create a plasma mirror on the surface of the affected 1 optical component that might deflect the extremely powerful laser pulse in an unpredictable direction and cause additional extensive damage to other expensive equipment located in the vicinity. As shown in several studies [9][10][11] , the bandgap of the material is strongly connected to the measured LIDT value. ...
With ultrafast laser systems reaching presently 10 PW peak power or operating at high repetition rates, research towards ensuring the long-term, trouble-free performance of all laser-exposed optical components is critical. Our work is focused on providing insight into the optical material behavior at fluences below the standardized laser-induced damage threshold (LIDT) value by implementing a simultaneous dual analysis of surface emitted particles using a Langmuir probe (LP) and the target current (TC). ${\mathrm{HfO}}_2$ and ${\mathrm{ZrO}}_2$ thin films deposited on fused silica substrates by pulsed laser deposition at various ${\mathrm{O}}_2$ pressures for defect and stoichiometry control were irradiated by Gaussian, ultrashort laser pulses (800 nm, 10 Hz, 70 fs) in a wide range of fluences. Both TC and LP collected signals were in good agreement with the existing theoretical description of laser–matter interaction at an ultrashort time scale. Our approach for an in situ LIDT monitoring system provides measurable signals for below-threshold irradiation conditions that indicate the endurance limit of the optical surfaces in the single-shot energy scanning mode. The LIDT value extracted from the LP-TC system is in line with the multipulse statistical analysis done with ISO 21254-2:2011(E). The implementation of the LP and TC as on-shot diagnostic tools for optical components will have a significant impact on the reliability of next-generation ultrafast and high-power laser systems.
... The peak power of femtosecond laser has been raised from terawatt (TW) level to petawatt (PW) level during the past decades. In recent years, multi-PW and 10 PW-class laser facilities have been constructed by many laboratories around the world, such as CoReLS 4.2 PW laser [2], SULF-10 PW laser [3], and ELI-10 PW laser [4]. However, limited by the available crystal size [5] and the inherent transverse parasitic lasing effect [6,7] in the Ti: sapphire crystal, it is not easy to directly boost the peak power to a higher level by using the CPA scheme. ...
Here, we report the recent progress on the front end developed for the 100 PW-class laser facility. Using 3 stages of optical parametric chirped-pulse amplification (OPCPA) based on lithium triborate (LBO) crystals, we realized a 5.26 J/0.1 Hz amplified output with a bandwidth over 200 nm near the center wavelength of 925 nm. After the compressor, we obtained a pulse duration of 13.4 fs. As the compression efficiency reached 67%, this OPCPA front end could potentially support a peak power of 263 TW at a repetition rate of 0.1 Hz. To the best of our knowledge, among all the 100 TW-level OPCPA systems, it shows the widest spectral width, the shortest pulse duration, and it is also the first OPCPA system working at a repetition-rate mode.
... [82] The relativistic lambda-cubed path would be one way to reach such high intensities [191]. Another approach is to combine existing [165,131] and forthcoming [251] multi-PW lasers capable of reaching focused laser intensities ∼ 10 23 W.cm −2 with curved plasma mirrors (Ąg 7.34). The idea is to focus the PW laser on a plasma mirror so that, under the right conditions (plasma gradient scale length), the reĆected beam contains higher frequencies/temporally compressed optical cycles (it is "Doppler boosted"). ...
Cette thèse expérimentale s’est essentiellement déroulée au Laboratoire d’Optique Appliquée à Palaiseau (France), sur un système laser capable de générer des impulsions proches du cycle optique en durée avec des énergies de plusieurs mJ à une cadence de 1 kHz : la Salle Noire 2. Ce système laser Titane:Sapphire est double CPA avec un filtre non-linéaire entre les deux étages (basé sur la génération d’onde de polarisation croisée ou ‘XPW’) pour améliorer le contraste temporel, suivi d’un étage de post-compression dans une fibre flexible étirée à cœur creux. Grâce à ce système, nous étudions l’interaction laser-matière en régime relativiste à haute cadence. Nous parvenons, d’une part, dans des jets de gaz, à accélérer des électrons dans le sillage du laser jusqu’ à une énergie de quelques MeV; et d’autre part, par interaction avec des miroirs plasma, à générer des harmoniques d’ordres élevés qui sont associées dans le domaine temporel à des impulsions attosecondes. Malgré la prouesse technique de ces expériences, les propriétés des faisceaux XUV et d’électrons ainsi générés restent encore peu compatibles avec des applications phares en aval. À la suite de travaux précédents en Salle Noire 2, l’objectif de cette thèse était d’obtenir des faisceaux aux propriétés stables, ce qui a été accompli en rendant le système laser plus stable et fiable, ainsi qu’en implémentant une boucle de contrôle rapide de la phase enveloppe-porteuse des impulsions laser. En variant la phase enveloppe-porteuse, nous avons ainsi pu générer des impulsions attosecondes uniques en formant une porte temporelle d’intensité relativiste à la surface du miroir plasma, et aussi produire des faisceaux d’électrons stables en énergie et en direction, en contrôlant l’injection d’ électrons dans l’accélérateur laser-plasma. De plus, différents régime d’interaction avec les miroirs plasma ont été étudiés expérimentalement, tels que l’accélération d’électrons dans les longs gr adients de densité plasma, et l’accélération de protons en face avant de la cible (la face sur laquelle le laser est incident) le long de la direction normale à la cible, afin de mesurer de nouvelles observables (spectre d’énergie des électrons, divergence des faisceaux de protons) et ainsi mieux comprendre la dynamique d’interaction laser-plasma.
https://theses.hal.science/tel-03957608
Laser-driven X-rays as probes for high-energy-density physics spans an extremely large parameter space with laser intensities varying by 8 orders of magnitude. We have built and characterized a soft X-ray source driven by a modest intensity laser of 4 × 10 ¹³ W/cm ² . Emitted X-rays were measured by diamond radiation detectors and a filtered soft X-ray camera. A material-dependence study on Al, Ti, stainless steel alloy 304, Fe, Cu and Sn targets indicated 5-μm-thick Cu foils produced the highest X-ray yield. X-ray emission in the laser direction and emission in the reverse direction depend strongly on the foil material and the thickness due to the opacity and hydrodynamic disassembly time. The time-varying X-ray signals are used to measure the material thinning rate and is found to be ∼1.5 μm/ns for the materials tested implying thermal temperature around 0.6 eV. The X-ray spectra from Cu targets peaks at ∼2 keV with no emission >4 keV and was estimated using images with eight different foil filters. One-dimensional hydrodynamic and spectral calculations using HELIOS-CR provide qualitative agreement with experimental results. Modest intensity lasers can be an excellent source for nanosecond bursts of soft X-rays.
High-energy lasers have benefited from intense efforts to bring light-matter interactions to new standards and to achieve laser fusion ignition. One of the main issues to further increasing laser energy is the resistance of optical materials to high laser fluences, in particular at the final stage of the laser beamline where nonlinear Kerr effects can occur in optical materials and provoke laser filamentation. One promising way to mitigate this process is to reduce the nonlinear susceptibility of the material by switching the polarization from a linear to a circular state. Here, we report a significant reduction in the laser filamentation effect on glass by using a full-silica metamaterial waveplateable to switch the linear-to-circular polarization of high fluence laser beams. This result is achieved through the use of a large size full-silica meta-optics exhibiting nominal polarization conversion associated with an excellent transmission efficiency and wavefront quality, as well as a high laser damage resistance.
Compressing high-energy laser pulses to a single-cycle and realizing the “λ^3 laser concept”, where λ is the wavelength of the laser, will break the current limitation of super-scale projects and contribute to the future 100-petawatt and even Exawatt lasers. Here, we have realized ultra-broadband gold gratings, core optics in the chirped pulse amplification, in the 750–1150 nm spectral range with a > 90% −1 order diffraction efficiency for near single-cycle pulse stretching and compression. The grating is also compatible with azimuthal angles from −15° to 15°, making it possible to design a three-dimensional compressor. In developing and manufacturing processes, a crucial grating profile with large base width and sharp ridge is carefully optimized and controlled to dramatically broaden the high diffraction efficiency bandwidth from the current 100–200 nm to over 400 nm. This work has removed a key obstacle to achieving the near single-cycle 100-PW lasers in the future.
