Plasma dynamics of water breakdown at a water surface induced by femtosecond laser pulses

Sarpe-Tudoran, C.; Assion, A.; Wollenhaupt, M.; Winter, Martin; Baumert, Thomas

doi:10.1063/1.2217158

Cited by 52 publications

(23 citation statements)

References 23 publications

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“…Within the calculations, a degree of ionization of Z = 1 is assumed. The model reproduces accurately the expansion velocities, measured in a water jet during interaction with a laser pulse [44]. Figure 2(b) depicts the decrease of the density of the target with time for three different intensities of the pump pulse.…”

Section: Resultsmentioning

confidence: 71%

High-order-harmonic generation from dense water microdroplets

et al. 2013

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We report on high-order-harmonic generation from micrometer-sized liquid water droplets. In pump-probe experiments, the influence of the time delay onto the emission of harmonic radiation is systematically studied. Phase-matching aspects are observed by controlling the focal position and the intensity of the probe pulse. The spatiotemporal dynamics of the droplet during interaction with intense laser pulses are studied by controlling the intensity of the pump pulse. We find transient phase-matching conditions and the expansion dynamics of the droplet to be of major influence on the harmonic yield.

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Section: Resultsmentioning

confidence: 71%

High-order-harmonic generation from dense water microdroplets

et al. 2013

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“…9,10 The temporal evolution of the free-electron density and the role of the fundamental ionization processes are strongly depending on time and intensity. 11,12 Two main processes for generating free electrons are multi photon ionization (MPI) and Avalanche-Ionization (AI). MPI requires no free initial free electrons and has highest efficiency for shortest pulses AI on the other hand needs initial free electrons and needs time to establish.…”

Section: Introductionmentioning

confidence: 99%

Temporal femtosecond pulse tailoring for nanoscale laser processing of wide-bandgap materials

et al. 2010

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Nanoscale laser processing of wide-bandgap materials with temporally shaped femtosecond laser pulses is investigated experimentally. Femtosecond pulse shaping in frequency domain is introduced and applied to two classes of shaped pulses relevant to laser nano structuring. The first class, characterized by a symmetric temporal pulse envelope but asymmetric instantaneous frequency allows us to examine the influence of the sweep of the photon energy. In contrast, asymmetric temporal pulse envelopes with a constant instantaneous frequency serve as a prototype for pulses with time-dependent energy flow but constant photon energy. In our experiment, we use a modified microscope set up to irradiate the surface of a fused silica sample with a single shaped pulse resulting in ablation structures. The topology of the laser generated structures is measured by Atomic Force Microscopy (AFM). Structure parameters are investigated as a function of the pulse energy and the modulation parameters. We find different thresholds for surface material modification with respect to an asymmetric pulse and its time reversed counterpart. However, we do not observe pronounced differences between up-and down-chirped radiation in the measured structure diameters and thresholds.

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“…This question has been experimentally addressed by studying the pulse duration dependence of the breakdown threshold, I th , [11][12][13][17][18][19][20][21] or of focal transmittance [22], by investigating the temporal dynamics of free electron density at individual laser parameters via spectral interferometry [23][24][25][26][27][28] or time-resolved reflectivity measurements [29][30][31], or by exploring nonlinear absorption associated with femtosecond filamentation [32]. The interplay of AI and SFI was then assessed by comparing model predictions to the experimental data.…”

Section: Sfi Consists Of Multiphoton Ionization (Mpi) and Tunneling Imentioning

confidence: 99%

Wavelength dependence of femtosecond laser-induced breakdown in water and implications for laser surgery

et al. 2016

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The wavelength dependence of the threshold for femtosecond optical breakdown in water provides information on the interplay of multiphoton, tunneling and avalanche ionization, and is of interest for parameter selection in laser surgery. We measured the bubble threshold from UV to near-IR wavelengths and found a continuous decrease of the irradiance threshold with increasing wavelength λ. Results are compared to the predictions of a numerical model that assumes a bandgap of 9.5 eV and considers the existence of a separate initiation channel via excitation of valence band electrons into a solvated state followed by rapid upconversion into the conduction band. Fits to experimental data yield an electron collision time of ≈ 1 fs, and an estimate for the capacity of the initiation channel. Using that collision time, the breakdown dynamics was explored up to λ = 2 µm. The irradiance threshold first continues to decrease but levels out for wavelengths longer than 1.3 µm. This opens promising perspectives for laser surgery at wavelengths around 1.3 µm and 1.7 µm, which are attractive because of their large penetration depth into scattering tissues.

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Plasma dynamics of water breakdown at a water surface induced by femtosecond laser pulses

Cited by 52 publications

References 23 publications

High-order-harmonic generation from dense water microdroplets

High-order-harmonic generation from dense water microdroplets

Temporal femtosecond pulse tailoring for nanoscale laser processing of wide-bandgap materials

Wavelength dependence of femtosecond laser-induced breakdown in water and implications for laser surgery

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