The objective of our contribution here is to demonstrate i the radiationchemical and radiobiological equivalence of ir laser filamentation to ionizing radiation in liquid or tissue equivalent liquid media, and ii the potential curative utility of femtosecond laser irradiation in an animal breast cancer model. In a first part, we describe the physical effects contributing to induce filamentation during the propagation of intense short laser pulses through transparent media. Weiwei liu institute of modern optics, nankai university. Pdf powerful femtosecond laser pulses propagate in an apparent form of filamentation in all transparent optical media. Powerful femtosecond laser pulses propagate in an apparent form of filamentation in all transparent optical media. Strong spatial confinement of terahertz wave inside. Numerical modelling of laser filamentation spie digital library. Supercontinuum generation by cofilamentation of two color. Femtosecond laser filamentation occurs as a dynamic balance between the selffocusing and plasma defocusing of a laser pulse to produce ultrashort radiation as brief as a few optical cycles.
Gaussian beam propagation predicts an increasing beam width bidirectionally away from the geometric focus. This type of propagation was called filamentation or selfguided propagation. Some fundamental concepts of femtosecond laser filamentation. Read femtosecond laser filamentation by see leang chin available from rakuten kobo. Everyday low prices and free delivery on eligible orders. Sep 18, 2012 the objective of our contribution here is to demonstrate i the radiationchemical and radiobiological equivalence of ir laser filamentation to ionizing radiation in liquid or tissue equivalent liquid media, and ii the potential curative utility of femtosecond laser irradiation in an animal breast cancer model. We experimentally investigate generation of backward 357 nm n2 laser in a gas mixture of n2ar using 800nm femtosecond laser pulses, and examine the involved gain dynamics based on pumpprobe measurements. The physical effects leading to filament formation of intense femtosecond laser pulses propagating in air will be introduced.
Femtosecond laser filamentation with various orders of mathieu. Powerful femtosecond laser pulses propagating in transparent materials result in the formation of selfguided structures called filaments. Shortly afterwards, filamentation of femtosecond laser pulses was shown to occur over more than 50 m in laboratoire doptique appliquee, see fig. Comparative study of femtosecond filamentation properties. Advances in intense femtosecond laser filamentation in air. Laser filamentation of a femtosecond pulse in air at 400nm t. This book attempts to give a discussion of the physics and current and potential applications of the selffocusing of an. Spatiotemporal evolution scenarios of femtosecond laser pulse filamentation in fused silica. The propagation of a high peak power femtosecond laser pulse through a dielectric medium results in filamentation, a strongly nonlinear regime characterized by a narrow, high intensity core surrounded by a lower intensity energy reservoir region. Femtosecond laser pulse filamentation versus optical. Mar 01, 2007 femtosecond filamentation in transparent media femtosecond filamentation in transparent media couairon, a mysyrowicz, a.
Maintaining pulse energies above the critical selffocusing limit produced filaments that were used for micromachining purposes. Cofilamentation of femtosecond laser pulses in gases was proposed as a powerful tool for controlling the collapse distance and the supercontinuum spectrum 16. Selffocusing and filamentation of femtosecond pulses in. We thus start with a very brief description of the fundamental physics of single filamentation of powerful femtosecond laser pulses in air. Simulations show that for the case of zeroorder mathieu beam, the onaxis filament together with two side filaments are formed, whereas the firstorder and secondorder mathieu beams can generate the onaxis filaments twice due to the diffractionfree property. Comparative study of femtosecond filamentation properties in. Citeseerx document details isaac councill, lee giles, pradeep teregowda.
Microfabrication of transparent materials using femtosecond laser pulses has showed good potential towards industrial application. First, the selffocusing of ultrashort laser pulses creates a plasma of lees 6. This work compares computational methods for laser pulse propagation in hollow waveguides filled with rare gases at high pressures, with applications in. Filamentation of intense femtosecond laser pulses in transparent dielectric media is a universal nonlinear. Filamentation in atmospheric air with tunable 11002400 nm.
This book attempts to give a discussion of the physics and current and potential applications of the selffocusing of an intense femtosecond laser pulse in a tra. The process of thirdharmonic generation during the filamentation of intense ir femtosecond laser pulses in air is investigated experimentally. Recent developments in femtosecond filamentation iopscience. Femtosecond laser filamentation, which results from extreme nonlinear propagation of intense femtosecond laser pulses in transparent media, has been one of the hottest topics in recent years due to its potential applications, such as harmonic generation 14, terahertz generation 58, remote sensing 9, etc. Femtosecond laser filamentation springer series on atomic, optical, and plasma physics book 55 ebook. Spatiotemporal evolution scenarios of femtosecond laser. These fields were probed using lowemittance, highly relativistic electron bunches from a laser wakefield accelerator, and a. We show experimentally that an embarked terawatt femtosecond laser can significantly decrease this drag.
Pdf the competition between femtosecond laser pulse induced optical breakdown and femtosecond laser pulse filamentation in condensed matter is studied. Femtosecond laser filamentation with various orders of. This universal nonlinear phenomenon is currently an. From selffocusing light beams to femtosecond laser pulse filamentation sergei v chekalin and valeriy p kandidov postfilamentation multiple light channel formation in air hui gao, weiwei liu and see leang chin picosecond laser filamentation in air view the table of contents for this issue, or go to the journal homepage for more. It has been attributed to the formation of a plasma negative dielectric waveguide induced by the. Femtosecond filamentation in transparent media, physics. A systematic study of glass scribing is presented on the benefits of ultrafast laser burst trains in generating filamentation tracks to guide cleaving of glass substrates. 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. Osa efficient thirdharmonic generation through tailored. Femtosecond laser filamentation with a microlens array in air osa. These variations were used to compute the energy deposited in the flow by the laser filament see the supplementary materials. Such filamentation in air can be controlled to occur at a distance as far as a few kilometers, making it ideally suited for remote sensing of pollutants in the atmosphere.
Buy femtosecond laser filamentation springer series on atomic, optical, and plasma physics 2010 ed. The influence of laser chirp on the formation of femtosecond laser filamentation in ar was investigated for the generation of fewcycle highpower laser pulses. On the one hand, the high intensity inside the filaments can induce the fragmentation. However, in the situation of laser filamentation, the beam will quickly recollapse. Filamentation occurs when a high power, femtosecond laser pulse propagates through a medium and is selffocused kerr lensing by the intensity dependent refractive index n 2. Our findings show that a minimum lifetime of population inversion in the excited n2 molecules is required for generating intense backward nitrogen lasers, which is. Advances in intense femtosecond laser filamentation in air1. Backward air lasing actions induced by femtosecond laser.
Surf around, find the information you are looking for and enjoy. Midinfrared femtosecond laser pulse filamentation in. Jun 21, 2019 cofilamentation of femtosecond laser pulses in gases was proposed as a powerful tool for controlling the collapse distance and the supercontinuum spectrum 16. For short pulses of a few tenths of a femtosecond, optical field ionization is the dominating process for plasma generation in the filament. This unique source has many properties that make it attractive as a nonlinear optical tool for spectroscopy, such as propagation at high intensities over extended distances, selfshortening.
Laser filamentation mathematical methods and models andre. H films and nanoparticles are produced by the strong interactions with the intense laser fields ca. A computercontrolled spatial light modulator is used to engineer the pofs. Aug 31, 2011 31 august 2011 filamentation of femtosecond laser pulses as a source for radiotherapy. Review femtosecond laser filamentation for atmospheric sensing 2010 cached.
The condition for the formation of a single filament has been carefully examined using 28fs laser pulses with energy over 3 mj. Aug 19, 2019 filamentation occurs when a high power, femtosecond laser pulse propagates through a medium and is selffocused kerr lensing by the intensity dependent refractive index n 2. Pdf femtosecond laser pulse filamentation versus optical. During the femtosecond laser filamentation, the generated terahertz thz pulse has been found to be strongly confined inside the plasma channel, reaching a spatial diameter of a few tens of micrometers. The development of the filamentation process from the creation of a single filament to the. Sensors free fulltext femtosecond laser filamentation. This process is strongly influenced by the spatiotemporal dynamics of the laser pulse. Pdf conical forward thz emission from femtosecondlaser. The structure can propagate over many core diameterbased rayleigh ranges. The interplay of kerr selffocusing, plasma defocusing, and bursttrain accumulation effects in filament formation was characterized by timeresolved insitu microscopic imaging. Selfcompression of optical laser pulses by filamentation. Photochemical reactions of gaseous ethylene in femtosecond laser filaments are studied. Femtosecond laser filamentation for atmospheric sensing core. We present experimental measurements of the femtosecond timescale generation of strong magneticfield fluctuations during the interaction of ultrashort, moderately relativistic laser pulses with solid targets.
Laser filamentation of a femtosecond pulse in air at 400nm. The competition between femtosecond laser pulse induced optical breakdown and femtosecond laser pulse filamentation in condensed matter is studied both experimentally and numerically using water as an example. Optical spectroscopy using gasphase femtosecond laser. The fundamental physical mechanism responsible for the selffocussing, filamentation, supercontinuum generation and conical emission of a powerful ultrashort laser pulse in a transparent optical me.
Cancer radiotherapy based on femtosecond ir laserbeam. In the present study, we consider the selfregulated generation of spatially homogeneous low density plasma ldp microchannels as a high intensity ionization source arising from the multi filamentation of powerful femtosecond fs laser pulses in aqueous solutions. This effect was initiated by the thin hot air column created in front of the supersonic object by filamentation of the laser pulse. When powerful femtosecond laser pulses propagate in air, filaments appear as a result of the dynamic balance between kerr selffocusing and. Filamentation of femtosecond laser pulses in turbulent air. The coexistence of filamentation and breakdown is observed under tight focusing conditions. Such filamentation in air can be controlled to occur at a distance as far as a few kilometers, making it ideally suited for. Laser filamentation mathematical methods and models. Osa laser chirp effect on femtosecond laser filamentation.
Quantitative measurements of the properties of laser filaments at 400nm are presented. We have numerically studied the femtosecond laser filamentation with various orders of mathieu beam in air. In particular, a model of the downward vertical nonlinear propagation of intense femtosecond laser pulses launched from orbital altitude 400 km will be developed. Study objective this ariadna project will study femtosecond laser filamentation from orbital altitudes. During the past two decades, propagation of femtosecond laser pulse has attracted great attention both experimentally and theoretically. Experimental investigation of linear energy deposition. By launching an infrared pulse with femtosecond pulse over critical power p c r 3. Advances in femtosecond laser filamentation in air. In an effort to address efficiently all the above we have created this website, persuaded that it will prove useful for all the people involved in the field as well as others simply interested in it. We measured a 50% transient reduction of drag on a test model placed in a supersonic wind tunnel at mach 3. Control of femtosecond multifilamentation in glass by. It is shown that the introduction of a thin plasma string created by another femtosecond pulse, perpendicularly to the filaments path, dramatically reshapes the thirdharmonic beam into a bessellike farfield distribution, while at the same. This unique source has many properties that make it attractive as a nonlinear optical tool for spectroscopy, such as propagation at high intensities over extended distances, selfshortening, whitelight. Oct 18, 2010 in the case of filamentation of femtosecond airy beams, the self.
There is no other book in the market with such a thorough update on the topics of current research interest such as selffocusing, filamentation, fragmentation, etc. Femtosecond laser filamentation springer series on atomic. Our results show that the phenomenon of plasmadriven intensity clamping, which is paramount in femtosecond laser filamentation, holds for. This universal nonlinear phenomenon is currently an interesting topic of research. During filamentation, intensity usually saturates at levels which do not exceed a few 10 14 w cm2. Intensity clamping during femtosecond laser filamentation. Experimental investigation of linear energy deposition using femtosecond laser filamentation in a m3 supersonic flow. Femtosecond laser filamentation for atmospheric sensing. The laser field intensity is found to be an important parameter to determine the sp 2 sp 3 carbon ratio of the films and.
Femtosecond filamentation is a nonlinear optical propagation regime of high peak power ultrashort laser pulses characterized by an extended and narrow core region of high intensity whose length greatly exceeds the rayleigh range corresponding to the core diameter. Femtosecond laser filamentation see leang chin springer. Experimental study of filamentation and supercontinuum generation in lasermodified fused silica. We present a scheme for realizing femtosecond multi filamentation with designable quantity and locations of filaments, based on the control of multifocal spots formed by patterned optical fields pofs composed of multiple individual optical fields iofs. Filamentation and selfcompression of femtosecond laser. Recent developments and potential applications of filamentation will be described. Filamentation is a universal phenomenon when an ultrashort laser pulse could. Femtosecond filamentation in transparent media femtosecond filamentation in transparent media couairon, a mysyrowicz, a.
We have investigated the filamentation and selfcompression of femtosecond laser pulses in different optical media such as argon gas and fused silica by employing a model developed in the frequency domain. An interesting phenomenon related to the filament propagation is the refocusing of focused laser pulses after the geometrical focus. Femtosecond laser filamentation ebook by see leang chin. In this paper, a new experimental phenomenon is demonstrated. With the aim of understanding the physics of filamentation in gases, solids. Femtosecond laser filamentation for atmospheric sensing ncbi. Improving supersonic flights with femtosecond laser. Improving supersonic flights with femtosecond laser filamentation. New opportunities for secure communication networks using. Filamentation of femtosecond laser pulses as a source for. Tuning the size of gold nanoparticles produced by multiple. Osa ultrafast laser bursttrain filamentation for non. Selffocusing and filamentation of femtosecond pulses in air.
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