Streak camera diagnostic of femtosecond laser spark

Garnov, S. V.; Konov, V. I.; Lozovoĭ, V. I.; Malyutin, A A; Schelev, Mikhail Ya.; Vorobiev, Nikolai S.

doi:10.1117/12.571805

Cited by 4 publications

(5 citation statements)

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“…It has been proposed earlier that the spatial distribution of energy in the focal volume of laser-induced breakdown actually determines what kind of postbreakdown dynamics the plasma will exhibit. This has been confirmed in studies of filamentation, ,,− where the choice of the focal length of the focusing lens influences the filamentation dynamics. In this context, the study of energy density , and energy balance has been done in several works where authors have studied laser-induced plasma formation using lasers with pulse duration from nanoseconds to femtoseconds.…”

Section: Introductionmentioning

confidence: 66%

Time- and Position-Dependent Breakdown Volume Calculations to Explain Experimentally Observed Femtosecond Laser-Induced Plasma Properties

et al. 2023

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Focusing of femtosecond laser pulses in gases can produce different gas breakdown phenomena depending on the focusing conditions: from simple optical breakdown like laser “sparks” to a nonlinear optical breakdown like filamentation. The dynamics of such plasmas after the pulse exposure is dependent on the energy deposited by the laser in the breakdown volume. Using a time- and position-dependent breakdown model, we estimate the breakdown volume and show that the energy deposited by the laser in this breakdown volume determines the characteristics of laser-induced plasma in the post-pulse exposure regime. Experimentally we find that for different focal lengths there exists a threshold value of the energy density beyond which a transition from an ellipsoidal shape to a spherical shape can be observed, followed by a toroidal expansion of the produced plasma. When electron density and electron temperature are expressed as a function of the energy density, deviations from the parabolic dependence on irradiance are observed. They imply additional ionization by multiphoton ionization in the plasma volume that occurs when the peak power of the laser pulse is above the critical power for self-focusing in air. The relevance of this experimental and theoretical study is to prevent undesired self-focusing conditions during material processing, a step toward well-controlled laser-plasma etching without laser ablation.

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Section: Introductionmentioning

confidence: 66%

Time- and Position-Dependent Breakdown Volume Calculations to Explain Experimentally Observed Femtosecond Laser-Induced Plasma Properties

et al. 2023

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“…The mutually perpendicular arrangement of the spectrometer dispersion plane and the SC sweep direction afforded the observation of twodimensional spectral-temporal pictures of the plasma emission. In our experiments we used a SC developed at the A.M. Prokhorov General Physics Institute, Russian Academy of Sciences [4][5][6][7]. This SC possessed a high spectral responsivity (2.1 mA/W at λ=800 nm; S1 photocathode) and a sufficiently broad dynamic range (no less than 10), which allowed us to reliably record and study the spectral-temporal dynamics of the femtosecond plasma emission in a broad wavelength range (λ=300-1100 nm) with a temporal resolution of 2.4 ps for a sweep speed up to 5× 10 9 cm/s.…”

Section: Ultrafast Spectroscopy Of Gas Plasmamentioning

confidence: 99%

Femtosecond laser breakdown of gases and transparent solid states: ultrafast space-time and spectrum-time resolved diagnostics of multicharged microplasma

Garnov

Bukin

Strelkov

et al. 2008

Laser-Induced Damage in Optical Materials: 2008

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We present the results of experimental studies of formation and evolution of multiply ionized (multicharged) laser micro-size plasma produced in gases (air, nitrogen, argon and helium) and inside the transparent solids (fused silica) with high intensity (up to ~ 10 17 W/cm 2 ), ultrashort (τ ~100 fs), 800nm/400nm laser pulses tightly focused in a region of ~1.5 μm in diameter. The measuring techniques and experimental setups for generation and precise optical diagnostics of laser-induced plasma -pump-probe microinterferometry and ultrafast spectroscopy are described. The measured spatiotemporal distributions of plasma refractive index/electron density and plasma spectra are demonstrated. In the experiments, the main attention was paid to the most intriguing initial stage of ultrafast plasma formation and evolution characterized by strong laser-matter and laser-plasma coupling resulting in efficient photoionization of material and plasma heating. We found out that the almost complete ionization (down to nuclei) of the initial gas occurs even at the initial stage of plasma formation. Besides, it was observed, for the first time, that a characteristic time of laser plasma formation considerably (in times) exceeds the duration of the pump laser pulse. This postionization process is attributed to impact ionization of plasma by hot electrons heated due to inverse bremsstrahlung. A theoretical model describing the mechanism of plasma postionization by hot photoelectrons was proposed. We compare the results of the experiments with what the theory predicts -the results of electron density calculations are in good agreement with the experimental data. The dynamics of plasma emission (spectral continuum and spectral line formation) in UV-visible spectral range was investigated with a picosecond time resolution applying the developed ultrafast streak-camera-based spectrometer. The spatiotemporal distributions of refractive index of laser irradiated fused silica were recorded with pump-probe microinterferometry. It was demonstrated that the induced refractive index of laser-matter interaction area changes its sign from the positive to the negative during the laser irradiation and again to the positive one after the laser pulse ends.

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“…The mutually perpendicular arrangement of the spectrometer dispersion plane and the SC sweep direction afforded the observation of two-dimensional spectral-temporal pictures of plasma emission. In our experiments we used a SC developed at the A.M. Prokhorov General Physics Institute, Russian Academy of Sciences [4][5][6][7]. This SC possessed a high spectral responsivity (2.1 mAAV at A,=800 nm; SI photocathode) and a sufficiently broad dynamic range (no less than 10), which allowed us to reliably record and study the spectral-temporal dynamics of the femtosecond plasma emission in a broad wavelength range (?i=300-1100 nm) with a temporal resolution of 2.4 ps for a sweep speed up to 5x10^ cm/s.…”

Section: Ultrafast Spectroscopy Of Gas Plasmamentioning

confidence: 99%

“…More recently these techniques were substantially modified and employed to investigate femtosecond microplasmas [3,4]. In addition we proposed a method for ultrafast electro-optical recording the emission spectra of laser-produced microplasma [3,[5][6][7].…”

Section: Introductionmentioning

confidence: 99%

Ultrafast Space-time and Spectrum-time Resolved Diagnostics of Multicharged Femtosecond Laser Microplasma

Garnov¹,

Bukin²,

Malyutin³

et al. 2009

AIP Conference Proceedings

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Articles you may be interested inWall current probe: A non-invasive in situ plasma diagnostic for space and time resolved current density distribution measurement Rev. Sci. Instrum. 84, 083502 (2013); Abstract. We present the review of the recent experimental studies of fundamental mechanisms of femtosecond laser plasma formation and evolution performed in A.M. Prokhorov General Physics Institute of Russian Academy of Sciences. The main object we dealt with was the microsized plasma produced in gases with high intensity (up to 5xlO" W/cm^), tightly focused (to a few microns in diameter) IR and UV femtosecond laser pulses. The main attention in the experiments was paid to the initial stage of microplasma formation and evolution characterized by strong laser-plasma coupling resulting in efficient ionization and heating of the medium, distortion of laser beam, and nonlinear spectral conversion of laser radiation to the continuum and laser harmonics. Using a precise pump-probe micro-interferometric technique the dynamics of plasma was studied with femtosecond time-resolution in a wide density range -from a minimal detectable electron concentration (lO" cm"') to the almost total (down to nuclei) ionization of ions occurred under femtosecond excitation. The obtained time-dependences of plasma density were analyzed. It was observed, for the first time, that a characteristic time of femtosecond laser plasma formation in gases considerably (in times) exceeds the duration of the pump laser pulse. This postionization process is attributed to impact ionization of plasma by hot electrons. We compare the results of the experiments with what the developed theory predicts. Using an ultrafast streak-camera-based spectroscopy technique the temporal evolution of microplasma emission and the dynamics of spectral lines formation in UV-visible range were studied with picosecond time-resolution.

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Streak camera diagnostic of femtosecond laser spark

Cited by 4 publications

References 0 publications

Time- and Position-Dependent Breakdown Volume Calculations to Explain Experimentally Observed Femtosecond Laser-Induced Plasma Properties

Time- and Position-Dependent Breakdown Volume Calculations to Explain Experimentally Observed Femtosecond Laser-Induced Plasma Properties

Femtosecond laser breakdown of gases and transparent solid states: ultrafast space-time and spectrum-time resolved diagnostics of multicharged microplasma

Ultrafast Space-time and Spectrum-time Resolved Diagnostics of Multicharged Femtosecond Laser Microplasma

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