Author: Publisher:
ISBN:
Category :
Languages : en
Pages : 2
Book Description
Laser Filamentation of a Femtosecond Pulse in Air at 400nm
Author: Femtosecond Laser Filamentation
Author: See Leang ChinPublisher: Springer Science & Business Media
ISBN: 1441906886
Category : Science
Languages : en
Pages : 138
Book Description
This book attempts to give a discussion of the physics and current and potential applications of the self-focusing of an intense femtosecond laser pulse in a tra- parent medium. Although self-focusing is an old subject of nonlinear optics, the consequence of self-focusing of intense femtosecond laser pulses is totally new and unexpected. Thus, new phenomena are observed, such as long range lam- tation, intensity clamping, white light laser pulse, self-spatial ltering, self-group phase locking, self-pulse compression, clean nonlinear uorescence, and so on. Long range propagation at high intensity, which is seemingly against the law of diffraction, is probably one of the most exciting consequences of this new sub- eld of nonlinear optics. Because the intensity inside the lament core is high, new ways of doing nonlinear optics inside the lament become possible. We call this lamentation nonlinear optics. We shall describe the generation of pulses at other wavelengths in the visible and ultraviolet (UV) starting from the near infrared pump pulse at 800 nm through four-wave-mixing and third harmonic generation, all in gases. Remotely sensing uorescence from the fragments of chemical and biological agents in all forms, gaseous, aerosol or solid, inside the laments in air is demonstrated in the labo- tory. The results will be shown in the last part of the book. Through analyzing the uorescence of gas molecules inside the lament, an unexpected physical process pertaining to the interaction of synchrotron radiation with molecules is observed.
Laser Filamentation
Author: Andre D. BandraukPublisher: Springer
ISBN: 3319230840
Category : Science
Languages : en
Pages : 223
Book Description
This book is focused on the nonlinear theoretical and mathematical problems associated with ultrafast intense laser pulse propagation in gases and in particular, in air. With the aim of understanding the physics of filamentation in gases, solids, the atmosphere, and even biological tissue, specialists in nonlinear optics and filamentation from both physics and mathematics attempt to rigorously derive and analyze relevant non-perturbative models. Modern laser technology allows the generation of ultrafast (few cycle) laser pulses, with intensities exceeding the internal electric field in atoms and molecules (E=5x109 V/cm or intensity I = 3.5 x 1016 Watts/cm2 ). The interaction of such pulses with atoms and molecules leads to new, highly nonlinear nonperturbative regimes, where new physical phenomena, such as High Harmonic Generation (HHG), occur, and from which the shortest (attosecond - the natural time scale of the electron) pulses have been created. One of the major experimental discoveries in this nonlinear nonperturbative regime, Laser Pulse Filamentation, was observed by Mourou and Braun in 1995, as the propagation of pulses over large distances with narrow and intense cones. This observation has led to intensive investigation in physics and applied mathematics of new effects such as self-transformation of these pulses into white light, intensity clamping, and multiple filamentation, as well as to potential applications to wave guide writing, atmospheric remote sensing, lightning guiding, and military long-range weapons. The increasing power of high performance computers and the mathematical modelling and simulation of photonic systems has enabled many new areas of research. With contributions by theorists and mathematicians, supplemented by active experimentalists who are experts in the field of nonlinear laser molecule interaction and propagation, Laser Filamentation sheds new light on scientific and industrial applications of modern lasers.
Control of Filamentation of Intense Femtosecond Laser Pulses Propagating in Air
Author: S. Abbas HosseiniFemtosecond Laser Pulses
Author: Claude RullierePublisher: Springer Science & Business Media
ISBN: 0387017690
Category : Science
Languages : en
Pages : 438
Book Description
This is the second edition of this advanced textbook written for scientists who require further training in femtosecond science. Four years after pub- cation of the ?rst edition, femtosecond science has overcome new challenges and new application ?elds have become mature. It is necessary to take into account these new developments. Two main topics merged during this period that support important scienti?c activities: attosecond pulses are now gen- ated in the X-UV spectral domain, and coherent control of chemical events is now possible by tailoring the shape of femtosecond pulses. To update this advanced textbook, it was necessary to introduce these ?elds; two new ch- ters are in this second edition: “Coherent Control in Atoms, Molecules, and Solids”(Chap.11)and“AttosecondPulses”(Chap.12)withwell-documented references. Some changes, addenda, and new references are introduced in the ?rst edition’s ten original chapters to take into account new developments and updatethisadvancedtextbookwhichistheresultofascienti?cadventurethat started in 1991. At that time, the French Ministry of Education decided that, in view of the growing importance of ultrashort laser pulses for the national scienti?c community, a Femtosecond Centre should be created in France and devoted to the further education of scientists who use femtosecond pulses as a research tool and who are not specialists in lasers or even in optics.
Summaries of Papers Presented at the Quantum Electronics and Laser Science Conference
Author: Energy Deposition in Air from Femtosecond Laser Filamentation for the Control of High Voltage Spark Discharges
Author: Guillaume PointImpact of Plasma Dynamics On Femtosecond Filamentation
Author: Rhys Mullin EmmsPublisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
In this thesis we ran a series of 2D simulations of femtosecond laser pulses filamenting in air using the FDTD method, a saturable Lorentz oscillator model of air [1], and two separate models of plasma: a Drude model where the plasma density is static in space, and a particle-in-cell model where plasma is free to migrate throughout the simulation space. By comparing matched pairs of simulations, which varied in pulse size, duration, and intensity, we can gauge the impact plasma dynamics has upon the evolution of a filamenting laser pulse. From these tests we determine that, while there are some visible differences between dynamic and static plasmas, plasma dynamics do not significantly alter the evolution of the pulse.
TRANSIENT OPTICAL NONLINEARITIES ENGENDERED BY FEMTOSECOND LASER FILAMENTATION IN GASES
Author: Suyash BajpaiPublisher:
ISBN:
Category :
Languages : en
Pages : 0
Book Description
The laser filamentation process in gases and its consequences have been at the center of interest over the three recent decades. The filament wake channel is formed by the laser pulse as a highly nonequilibrium and optically underdense plasma column. The contents of the plasma evolve towards equilibrium, giving rise to various transient optical effects. When filamentation occurs in a dense gas, it leads to the production of the excessively high density of excited atoms as compared to the density of ions. We used a kinetic model of the competing electron-collisional processes in the case of high-pressure argon gas and explored the sensitivity of the resulting excited-to-ionized atoms number density ratio to the envelope shape of the driving laser pulse. Considering three different families of the pulse shapes, we have shown that the ratio of excited atoms to ions in the dense gas can be manipulated and further increased. To further investigate the structure of the plasma column, we studied the filamentation process at the crossing of two laser beams. We have shown that in this case the process is significantly affected by the transient intensity grating caused by the beam interference in the crossing area, which leads to the formation of a microscopically structured filament wake channel. In particular, the grating of excited atom density is formed in the channel. We obtained characteristics of such excitation gratings that are controlled by the spatial and temporal characteristics of the crossing pulses. A nonlinear optical effect that is crucial in the context of excess excited atoms is the Rabi sideband generation. The Rabi sideband patterns from a one-dimensional plasma channel have already been studied. We considered theoretically the probing of the above-mentioned excitation gratings by a picosecond laser beam of 800 nm carrier wavelength and the formation of the characteristic spatial-spectral patterns of the Rabi sidebands. We demonstrated the sensitivity of these Rabi sideband patterns towards the grating characteristics, probe beam shape and wavelength and to the position of the observation screen and the observation slit on the screen. As our capstone work, we explored filamentation of long-wavelength laser pulses in atmospheric-pressure gases, as this situation effectively meets the dense gas criteria. We worked at transforming the theoretical and computational techniques that we developed for high-pressure gases at typical laser wavelengths (~800 nm) to be applicable to atmospheric-pressure gases at longer laser wavelengths (~3900 nm). Intense, ultrashort laser pulses of these latter carrier wavelength values just recently have become available for experiments and carry a great promise for applications in atmospheric optics, atmospheric chemistry, and related disciplines.
Optically Induced Nanostructures
Author: Karsten KönigPublisher: Walter de Gruyter GmbH & Co KG
ISBN: 3110383500
Category : Science
Languages : en
Pages : 360
Book Description
Nanostructuring of materials is a task at the heart of many modern disciplines in mechanical engineering, as well as optics, electronics, and the life sciences. This book includes an introduction to the relevant nonlinear optical processes associated with very short laser pulses for the generation of structures far below the classical optical diffraction limit of about 200 nanometers as well as coverage of state-of-the-art technical and biomedical applications. These applications include silicon and glass wafer processing, production of nanowires, laser transfection and cell reprogramming, optical cleaning, surface treatments of implants, nanowires, 3D nanoprinting, STED lithography, friction modification, and integrated optics. The book highlights also the use of modern femtosecond laser microscopes and nanoscopes as novel nanoprocessing tools.