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Currents circulating in the plasma column of filaments in air are detected with a fast current monitor. The currents can be amplified with circularly polarized light.
Spontaneous currents inside the plasma column of filaments of N2 and Argon circulate in opposite directions. A competition between the laser Lorentz force and a Coulomb wake force explains the difference.
We experimentally demonstrate that high energy femtosecond laser pulses can be compressed using nonlinear propagation in gas-filled planar hollow waveguides. A stability analysis provides guidelines for up-scaling the compressible pulse energy without spatial beam-breakup.
We experimentally demonstrate the revival of short lived femtosecond laser induced plasma channels in air by a nanosecond laser pulse up to several milliseconds after plasma recombination. Such revived plasma channel is generated over 50 cm using a Bessel-like nanosecond laser beam.
Compression of ultrashort laser pulses by self-phase modulation in a gas-filled planar hollow waveguide is studied both experimentally and theoretically. This technique outperforms significantly other techniques based on hollow core fibers or filamentation.
Several concepts for the compression of ultrashort laser pulses to the few-cycle regime were recently proposed. Most promising among these are filamentation in gases as well as nonlinear propagation inside gas-filled hollow-core fibres. However, both methods are limited in terms of the accessible output pulse energy (typically below ~1 mJ), either by the onset of multiple filamentation for the first...
Summary form only given. Air plasma excited by a 800 nm femtosecond pulse with its second harmonic is capable of emitting intense terahertz (THz) radiation, which is of great interest due to its unique potential for stand-off THz applications. In this paper, we report the experimental observation of an electric dipole moment in such a plasma and its coherent control. In the experiment, a femtosecond...
We experimentally demonstrate the revival of short lived femtosecond laser induced plasma channels in air by a nanosecond laser pulse up to several milliseconds after plasma recombination. Such revived plasma channel is generated over 50 cm using a Bessel-like nanosecond laser beam.
We experimentally demonstrate that high energy ultrashort pulses can be compressed through self-phase-modulation in hollow planar waveguides. The beam is guided in one transverse dimension and propagates free in other, allowing scalability to higher energies.
We present experimental and theoretical results on the robustness, beam pointing accuracy and survival probability of femtosecond filaments in turbulent air.
Terahertz radiations of laser filament biased by an AC terahertz field or a DC electric field are studied. Similar physical properties of the two THz radiations are observed. Efficiency of both methods is compared.
We present experimental and theoretical results on the robustness, beam pointing accuracy and survival probability of femtosecond filaments in turbulent air.
We examine the generation of terahertz by optical rectification of fundamental infrared beam with its second harmonic in ionized air. From polarization measurements we identify an important, yet so far unreported cross term chixyxy(3).
By focusing ultrashort laser pulses in air with axicon, long and continuous plasma channels can be formed. The channel length is significantly longer than that obtained by filamentation with lens of same effective focal distance.
Summary form only given. Pulse compression through filamentation to the two-optical-cycle regime has been demonstrated, including its capability of maintaining the carrier-envelope-offset (CEO) phase. Simulations reproduce these results well but also indicate significant spatial structure in the output beam calling for spatio-temporal characterization of these pulses. We used 30-fs pulses centered...
We demonstrate new world-record pulse duration of only 4.9 fs with filamentation pulse compression, performed full spatio-temporal characterization and used an interferometric technique to experimentally determine the plasma density in the filament.
Filaments created in air by an intense femtosecond laser pulse in the presence of an electric field generate a highly conductive permanent plasma column.
Filaments created in air by an intense femtosecond laser pulse in the presence of an electric field generate a highly conductive permanent plasma column.
We measure a strong forward THz emission from femtosecond filaments in air and we attribute it to a Cerenkov emission from the ionization front moving at superluminal velocity.
This paper introduces and discusses the main aspects of ultrashort laser pulse filamentation in various transparent media such as air (gases), transparent solids and liquids. The properties of femtosecond filaments and their applications are presented. Theoretical models developed to explain filaments and the main predictions inferred from these models are reviewed. The various techniques to observe...
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