Sensitivity of propagation and energy deposition in femtosecond filamentation to the nonlinear refractive index

Rosenthal, Eric; Palastro, J. P.; Jhajj, N.; Zahedpour, S.; Wahlstrand, J. K.; Milchberg, H. M.

doi:10.1088/0953-4075/48/9/094011

Cited by 34 publications

(23 citation statements)

References 45 publications

(130 reference statements)

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“…For comparison, simulations performed with a 100 fs laser pulse of comparable peak intensity, the contribution to plasma density from avalanche multiplication amounts to 3-5 %. We have also calculated that the losses due to molecular rotation only amount to 5.5% of total losses in our case, while it can exceed 50% in the case of 130 fs pulse at 800 nm [12]. The use of the long pulse duration strongly decreases the losses due to Raman Effect.…”

Section: Simulationsmentioning

confidence: 55%

“…The pulse duration seems to have a stronger influence on the energy losses. By decreasing the pulse duration to 100 fs, Raman absorption becomes significant (as observed in [12,25]) and multiphoton ionization is strongly increased. The total energy losses are then raised to 20%.…”

Section: Comparison With Experimental Results and Discussionmentioning

confidence: 91%

“…Once the critical intensity for ionization is reached on the ascending part of the pulse, the rest of the pulse is reabsorbed by the plasma in an inverse bremhsstrahlung effect, leading to the rapid multiplication of free electrons and dielectric breakdown of the medium. Most of the laser energy is consumed locally at a distance fixed by the moving focus model [10][11][12].…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Study of filamentation with a high power high repetition rate ps laser at 103 µm

Houard¹,

Jukna²,

Point³

et al. 2016

Opt. Express

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We study the propagation of intense, high repetition rate laser pulses of picosecond duration at 1.03 µm central wavelength through air. Evidence of filamentation is obtained from measurements of the beam profile as a function of distance, from photoemission imaging and from spatially resolved sonometric recordings. Good agreement is found with numerical simulations. Simulations reveal an important self shortening of the pulse duration, suggesting that laser pulses with few optical cycles could be obtained via double filamentation. An important lowering of the voltage required to induce guided electric discharges between charged electrodes is measured at high laser pulse repetition rate.

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Section: Simulationsmentioning

confidence: 55%

Section: Comparison With Experimental Results and Discussionmentioning

confidence: 91%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Study of filamentation with a high power high repetition rate ps laser at 103 µm

Houard¹,

Jukna²,

Point³

et al. 2016

Opt. Express

View full text Add to dashboard Cite

show abstract

“…To demonstrate STOV generation in the arrest of self-focusing collapse, we perform simulations using Eq. (1), assuming azimuthal symmetry, and include electronic, rotational, and ionization nonlinearities in { } V ψ (18,20). The Gaussian input pulse is 3 mJ, 45 fs (Gaussian FWHM), with input waist w 0 =1mm.…”

Section: Spatio-temporal Optical Vortices (Stovs)mentioning

confidence: 99%

Spatio-Temporal Optical Vortices*

Jhajj

Larkin

Rosenthal

et al. 2016

Frontiers in Optics 2016

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We present the first experimental evidence, supported by theory and simulation, of spatiotemporal optical vortices (STOVs). Quantized STOVs are a fundamental element of the nonlinear collapse and subsequent propagation of short optical pulses in material media. A STOV consists of a ring-shaped null in the electromagnetic field about which the phase is spiral, forming a dynamic torus which is concentric with and tracks the propagating pulse. Depending on the sign of the material dispersion, the local electromagnetic energy flow is saddle or spiral about the STOV. STOVs are born and evolve conserving topological charge; they can be simultaneously created in pairs with opposite windings, or generated from a point null. Our results, here obtained for optical pulse collapse and filamentation in air, are generalizable to a broad class of nonlinearly propagating waves.

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“…We recently showed that in the near-infrared (pump wavelength e = 0.8 µm), air propagation simulations depend very sensitively on the values used for the coefficients (n2) describing the instantaneous electronic nonlinear response of air constituents [18]. Best agreement of the simulations with axially resolved measurements occurs for n2 coefficients measured in [19].…”

mentioning

confidence: 99%

Measurement of the Nonlinear Refractive Index of Air Constituents at Mid-Infrared Wavelengths

Zahedpour

Wahlstr

Milchberg

2016

High-Brightness Sources and Light-Driven Interactions

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We measure the nonlinear refractive index coefficients in N 2 , O 2 and Ar from visible through mid-infrared wavelengths ( = 0.4  2.4 µm). The wavelengths investigated correspond to transparency windows in the atmosphere. Good agreement is found with theoretical models of  (3) . Our results are essential for accurately simulating the propagation of ultrashort mid-IR pulses in the atmosphere.Filamentary propagation of intense ultrashort laser pulses in atmosphere for < ~1 m has been a subject of extensive study [1,2], finding applications in the generation of terahertz radiation [3], high harmonic generation [4], air lasing [5][6][7], and remote inscription of optical waveguides into air [813]. It has been anticipated that new regimes of laser filamentation are possible at longer wavelengths, such as in the midinfrared (mid-IR,  ~ 1.5-10 m), where beam collapse arrest may occur through harmonic walk-off rather than plasma-induced refraction [14]. Mid-IR filamentation is effective for generating coherent keV-level photon beams in high pressure gas-filled capillaries [15] and broad mid-IR supercontinua in high pressure gas volumes [16].Accurate values for nonlinear coefficients are essential for high fidelity simulations of intense laser propagation [17]-such simulations are indispensable not only for designing experiments and informing applications, but they also motivate the design and parameters of the lasers themselves. We recently showed that in the near-infrared (pump wavelength e = 0.8 µm), air propagation simulations depend very sensitively on the values used for the coefficients (n2) describing the instantaneous electronic nonlinear response of air constituents [18]. Best agreement of the simulations with axially resolved measurements occurs for n2 coefficients measured in [19].In this Article, we present measurements of n2 for the air constituents N2, O2 and Ar at pump wavelengths ranging from 400 nm to 2400 nm. The near through mid-IR wavelengths chosen (e = 1250 nm, 1650 nm, 2200 nm, 2400 nm) are within the transparency windows of air [20]. We find that the nonlinear response is quite dispersionless over the range of wavelengths investigated, except near e=400 nm, consistent with a simple model for the third-order nonlinear susceptibility developed by Bishop [21].The experimental setup is shown in Fig 1. Pulses from a 1 kHz Ti:Sapphire regenerative amplifier centered at 800 nm are split, with 2.8 mJ pumping an optical parametric amplifier (OPA) [22], which is tunable from 1100 nm to 2600 nm. A chopper reduces the pulse repetition rate to 500 Hz. The remaining portion of the 800 nm pulse is attenuated and weakly focused in a 2 atm xenon gas cell, where filamentation generates a =500700 nm broadband supercontinuum (SC) transmitted through the pump-rejecting dichroic splitter. A Michelson interferometer splits the SC into two collinear pulses (reference and probe) temporally separated by 2 ps. The dispersive glass in the SC beam path introduces equal positive chirp to ~1.5 ps on the reference ...

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Sensitivity of propagation and energy deposition in femtosecond filamentation to the nonlinear refractive index

Abstract: The axial dependence of femtosecond filamentation in air is measured under conditions of varying laser pulsewidth, energy, and focusing f-number.

Cited by 34 publications

References 45 publications

Study of filamentation with a high power high repetition rate ps laser at 103 µm

Study of filamentation with a high power high repetition rate ps laser at 103 µm

Spatio-Temporal Optical Vortices*

Measurement of the Nonlinear Refractive Index of Air Constituents at Mid-Infrared Wavelengths

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