Femtosecond filamentation of optical vortices for the generation of optical air waveguides

Fu, Silin; Mahieu, B.; Mysyrowicz, A.; Houard, Aurélien

doi:10.1364/ol.472143

Cited by 22 publications

(4 citation statements)

References 34 publications

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“…The use of vortex beams [11,12] to create plasma waveguides is promising because their helical phase front prevents the appearance of the field on the optical axis. This feature is conserved under the self-action of radiation and the annular distribution of plasma channels that form a cylindrical waveguide is thereby supported [13].…”

Section: Introductionmentioning

confidence: 85%

Channels of Filaments of Axially Asymmetric Optical Vortices at a Wavelength of 1800 nm in a LiF Crystal

et al. 2023

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The formation of a set of filaments and plasma channels in a femtosecond optical vortex has been studied experimentally and numerically. A longitudinal distribution of color center tracks with a length of 1 cm written in a LiF crystal by an axially asymmetric beam in the single-pulse regime has been detected experimentally for the first time. It has been shown that, at a sufficient excess of the peak power over the critical value, two hot points on the annular profile of vortex beam separated by the phase dislocation region form sequences of color center tracks; each sequence in the cross section of the beam is localized near the initial hot point. Secondary filaments and the corresponding tracks appear with an increase in the pulse energy. The parameters of femtosecond filaments in LiF have been numerically estimated.

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Section: Introductionmentioning

confidence: 85%

Channels of Filaments of Axially Asymmetric Optical Vortices at a Wavelength of 1800 nm in a LiF Crystal

et al. 2023

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“…Vortex filaments have gathered interest in recent years in part because they are very robust, even if they eventually may break into multiple filaments due to modulational instabilities. [23][24][25] Using a vortex filament also adds a new degree of freedom -the optical angular momentum -which can be desirable for optical communications, optical imaging and other applications. Furthermore, and specific to light propagation in air, vortex filaments can be utilized to create long-lived thermally-induced waveguides.…”

Section: Vortex Filaments and Thermal Waveguidingmentioning

confidence: 99%

Thermal effects and shockwave formation due to filaments in air

Bagley,

Upperman,

Rastegari

et al. 2024

Laser Resonators, Microresonators, and Beam Control XXVI

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A filament forms through a balance of self-focusing (Kerr effect) and plasma self-defocusing. The heat generated as the electron-ion recombine produces a cylindrical shock wave behind which a low-density channel is formed. High-energy UV filaments are used to study the shock wave by shadowgraphy. The shock is seen to start supersonic, before transitioning after microseconds to a constant velocity acoustic wave. Computational models of the gas-dynamics evolution are presented that agree with a well known empirical formula for shockwave velocity, as well as with experimental observations. We determine the profile of induced changes to the refractive index of air due to these thermal effects. We then simulate a vortex filament creating a parabolic index of refraction that can serve as a waveguide for successive filaments.

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“…This permits to reproducibly generate stable world-record average power above 40 W in the deep-UV, and produce clean beams that would be usable for long-distance filamentation applications. 11,12 This also makes it possible to address other limiting phenomena and make progress towards efficient and reliable industrial systems.…”

Section: Introductionmentioning

confidence: 99%

45 W average-power, high-energy deep-UV generation at 257 nm in LBO

Mennerat,

Bizet,

Mahieu

et al. 2024

Nonlinear Frequency Generation and Conversion: Materials and Devices XXIII

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We report on high average-power, high-energy picosecond fourth-harmonic generation in LBO. The first stages of a Yb:YAG laser chain operating at 1 kHz repetition rate generate few-picosecond 220 mJ chirped pulses at 1030 nm fundamental wavelength. They are frequency-converted in a cascade of three LBO crystals to generate the second-, third-, and fourth-harmonics at 515 nm, 343 nm and 257 nm respectively. Crystals thicknesses and angular phase-matching detuning were calculated as a function of pulse duration through broadband nonlinear optical numerical simulations. Last crystal is both conduction-cooled on edge and surface-cooled at center through forced-air flow to mitigate heating due to nonlinear absorption in the deep-UV and reduce temperature gradients. Chirped-pulse duration was experimentally adjusted to achieve stable 20% overall conversion efficiency. Near-field beam profiles were continuously recorded at 10 Hz, for all four wavelengths involved, together with corresponding energies, showing no significant beam degradation over 50 hours. Temperatures of the two last crystals were monitored, and will help optimize surface cooling for future power ramping-up.

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Femtosecond filamentation of optical vortices for the generation of optical air waveguides

Cited by 22 publications

References 34 publications

Channels of Filaments of Axially Asymmetric Optical Vortices at a Wavelength of 1800 nm in a LiF Crystal

Channels of Filaments of Axially Asymmetric Optical Vortices at a Wavelength of 1800 nm in a LiF Crystal

Thermal effects and shockwave formation due to filaments in air

45 W average-power, high-energy deep-UV generation at 257 nm in LBO

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