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Your search keyword '"Panagiotopoulos, Paris"' showing total 3 results
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3 results on '"Panagiotopoulos, Paris"'

1. Super high power mid-infrared femtosecond light bullet.

Author

Panagiotopoulos, Paris, Whalen, Patrick, Kolesik, Miroslav, and Moloney, Jerome V.

Subjects
*FEMTOSECOND lasers, *OPTICAL information processing, *LASER communication systems, *SUBMILLIMETER waves, *RADIO frequency
Abstract

Mid-infrared ultrashort high energy laser sources are opening up new opportunities in science, including keV-class high harmonic generation and monoenergetic MeV-class proton acceleration. As new higher energy sources become available, potential applications for atmospheric propagation can dramatically grow to include stand-off detection, laser communications, shock-driven remote terahertz enhancement and extended long-lived thermal waveguides to transport high power microwave and radiofrequency waves. We reveal a new paradigm for long-range, low-loss, ultrahigh power ultrashort pulse propagation at mid-infrared wavelengths in the atmosphere. Before the onset of critical self-focusing, energy in the fundamental wave continually leaks into shock-driven spectrally broadened higher harmonics. A persistent near-invariant solitonic leading edge on the multi-terawatt pulse waveform transports most of the power over hundred-metre-long distances. Such light bullets are resistant to uncontrolled multiple filamentation and are expected to spark extensive research in optics, where the use of mid-infrared lasers is currently much under-utilized. [ABSTRACT FROM AUTHOR]

Published
2015
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2. Exploring the limits to energy scaling and distant-target delivery of high-intensity midinfrared pulses.

Author

Panagiotopoulos, Paris, Kolesik, Miroslav, and Moloney, Jerome V.

Subjects
*NUMERICAL analysis, *SIMULATION methods & models, *ELECTRONIC modulation
Abstract

We numerically investigate the scaling behavior of midinfrared filaments at extremely high input energies. It is shown that, given sufficient power, kilometer-scale, low-loss atmospheric filamentation is attainable by prechirping the pulse. Fully resolved four-dimensional (xyzt) simulations show that, while in a spatially imperfect beam the modulation instability can lead to multiple hot-spot formation, the individual filaments are still stabilized by the recently proposed mechanism that relies on the temporal walk-off of short-wavelength radiation. [ABSTRACT FROM AUTHOR]

Published
2016
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3. Nonlinear plasma-assisted collapse of ring-Airy wave packets.

Author

Panagiotopoulos, Paris, Couairon, Arnaud, Kolesik, Miroslav, Papazoglou, Dimitris G., Moloney, Jerome V., and Tzortzakis, Stelios

Subjects
*COMPUTER simulation, *WAVE packets, *GAUSSIAN beams
Abstract

We numerically demonstrate that femtosecond ring-Airy wave packets are able to overcome the reference intensity clamping of 4?1013 W/cm² for filaments generated with Gaussian beams at low numerical apertures and form an intense sharp intensity peak on axis. Numerical simulations, with unidirectional propagation models for the pulse envelope and the carrier resolved electric field, reveal that the driving mechanism for this unexpected intensity increase is due to the self-generated plasma. The plasma formation, in conjunction with the circular geometry of the beam, force the wave packet into a multistage collapse process which takes place faster than the saturating mechanisms can compensate. We report here a nonstandard mechanism that increases the intensity of a collapsing wave packet, due to the joint contributions of the cubic phase of the Airy beam and the formation of a partially reflecting plasma. [ABSTRACT FROM AUTHOR]

Published
2016
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