Effect of intensity clamping on laser ablation by intense femtosecond laser pulses

Xu, Zhi; Liu, Weiwei; Zhang, N.; Wang, M.W.; Zhu, Xing

doi:10.1364/oe.16.003604

Cited by 12 publications

(5 citation statements)

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“…To measure the pulse shape within the filament, a 100 µm Al foil is placed in the filament path. The filament drills a self-adapted iris, arresting further filamentation and non-linear propagation [36], but preserving the temporal pulse shape at this distance. The remaining beam was analyzed by a SPIDER.…”

Section: Methodsmentioning

confidence: 99%

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Amplification of intense light fields by nearly free electrons

et al. 2018

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Light can be used to modify and control properties of media, as in the case of electromagnetically induced transparency or, more recently, for the generation of slow light or bright coherent XUV and X-ray radiation. Particularly unusual states of matter can be created by light fields with strengths comparable to the Coulomb field that binds valence electrons in atoms, leading to nearly-free electrons oscillating in the laser field and yet still loosely bound to the core [1,2]. These are known as Kramers-Henneberger states [3], a specific example of laser-dressed states [2]. Here, we demonstrate that these states arise not only in isolated atoms [4,5], but also in rare gases, at and above atmospheric pressure, where they can act as a gain medium during laser filamentation. Using shaped laser pulses, gain in these states is achieved within just a few cycles of the guided field. The corresponding lasing emission is a signature of population inversion in these states and of their stability against ionization. Our work demonstrates that these unusual states of neutral atoms can be exploited to create a general ultrafast gain mechanism during laser filamentation.

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Section: Methodsmentioning

confidence: 99%

“…We use ultra violet fused silica windows and lenses, for the cell and focusing into the spectrometers. Details of the broadband laser and pulse shaping and compression system can be found in Methods Refs [36]. and[38].…”

mentioning

confidence: 99%

Amplification of intense light fields by nearly free electrons

et al. 2018

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“…Importantly, if laser power is above the critical one P cr = 3.77λ 2 /8πn 0 n 1 , where n 0 and n 1 stand for the linear (1.34) and nonlinear refractive (≈ 0.4 × 10 −19 m 2 /W) indexes of the material [36], P cr = 7.4 × 10 5 W), the laser propagation of a Gaussian laser pulse is accompanied by such effects as self-focusing and filamentation [37]. Further increase in laser power becomes inefficient (a so-called "intensity clamping effect" [38]).…”

Section: Single-pulse Mechanismmentioning

confidence: 99%

Ultra-short laser-induced high aspect ratio densification in porous glass

Itina¹,

Zakoldaev²,

Sergeev³

et al. 2019

Opt. Mater. Express

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Multiple ultra-short laser irradiation enabling direct writing of high aspect ratio barriers is used for structuring of nanoporous glass. Shape and morphology of laser-modified regions are examined, and high aspect ratio laser-induced material densification is founded. Experimental results are analyzed by modeling describing laser propagation, non-linear ionization and thermal effects. The role of laser focusing, laser energy and pulse number are examined. Several regimes are distinguished. Particularly, high-aspect ratio densified zones are obtained for the numerical aperture of 0.25, whereas either more symmetric densified regions or spherical cavities are shown to be formed for numerical aperture of 0.4. The resulting laser irradiation conditions required for deep and prolonged densification are explained by a lower ionization rate, leading to the under-critical free electron plasma density, longer filamentation and pulse-to-pulse elongation effects. Furthermore, filling of the porous glass with water is demonstrated to particularly extend the length of the densified region in depth. The presented study provides insights facilitating laser-based fabrication of barriers, membrane and patterns suitable for the environmental gas-phase analysis.

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“…To optimize the SC, the crystal was adjusted with respect to the focus, resulting in minimal fluctuations of about 0.3% in shot-to-shot rms, similar to the fluctuations of the fiber laser itself. The excellent stability arises from intensity clamping, which is well known in bulk SC generation [1,2]. The remaining power of the fiber laser output was frequency doubled by second harmonic generation (SHG) to produce the pump beam for the NOPA in a 1-mm thick BBO crystal, resulting in 10 J per pulse of SHG output.The SC was combined with the frequency doubled part of the fiber laser output in a 3.5 mm thick BBO crystal under an angle of 2.3 • .…”

mentioning

confidence: 99%

Supplementary document for Transient field-resolved reflectometry at 50-100 THz - 5538130.pdf

Neuhaus,

Schötz,

Aulich

et al. 2022

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Supporting Information on 'Transient field-resolved reflectometry at 50-100 THz' MARCEL NEUHAUS et al. 1. Further details on the experimental setup 1.1. NOPAThe experimental setup for MIR field-resolved transient reflectometry is based on a non-collinear optical parametric amplifier (NOPA) delivering sub-8 fs pulses at around 800 nm, cf. Fig. 1. The NOPA is driven by a commercial fiber laser (Active Fiber Systems) source with an output of 1030 nm in wavelength and 540 fs pulse length, cf. Fig. 1 (a). The tunable repetition rate of the fiber laser (0.05-19 MHz) was set to 2.1 MHz and a pulse energy of 20 J.A part of the fiber laser output is used for producing the seed via super-continuum generation (SCG) in an 8 mm long YAG crystal with 1.5 J of the 1030 nm beam using a numerical aperture of 0.019. As the wavelength range around the fundamental is incompressible due to phase ripples, a 1000 nm short-pass filter was used to clip the SC at the long wavelength side. To optimize the SC, the crystal was adjusted with respect to the focus, resulting in minimal fluctuations of about 0.3% in shot-to-shot rms, similar to the fluctuations of the fiber laser itself. The excellent stability arises from intensity clamping, which is well known in bulk SC generation [1,2]. The remaining power of the fiber laser output was frequency doubled by second harmonic generation (SHG) to produce the pump beam for the NOPA in a 1-mm thick BBO crystal, resulting in 10 J per pulse of SHG output.The SC was combined with the frequency doubled part of the fiber laser output in a 3.5 mm thick BBO crystal under an angle of 2.3 • . A broadband NIR pulse is achieved spanning from 650-980 nm (see Fig. 1(b)). The NIR pulses are compressed by a combination of fused-silica wedges and a set of complementary chirped mirror pairs to a pulse duration below 8 fs at an energy of around 2 J (Fig. 1(c)). The spectral phase and pulse duration of NOPA output pulses are measured and retrieved using the dispersion scan (D-scan) technique.The shot-to-shot rms power stability of the NIR was as low as 0.4% with long-term (8 hours) power stability below 1% as can be seen in Fig. 2. To improve the pointing stability of the pulses, a beam pointing stabilizer (Aligna, TEM) is placed between the NOPA and successive iDFG stage.

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Effect of intensity clamping on laser ablation by intense femtosecond laser pulses

Cited by 12 publications

References 0 publications

Amplification of intense light fields by nearly free electrons

Amplification of intense light fields by nearly free electrons

Ultra-short laser-induced high aspect ratio densification in porous glass

Supplementary document for Transient field-resolved reflectometry at 50-100 THz - 5538130.pdf

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