Enhanced Harmonic Generation with Ultra-short Laser Pulses PDF Download
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Author: Ekaterina V. Sergan
Publisher:
ISBN:
Category : Bessel functions
Languages : en
Pages : 101
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Book Description
Table top short-pulsed UV lasers are coveted for their usefulness in time-resolved studies of molecular dynamics. However, current wave-mixing and harmonic generation techniques using crystals fail to preserve the short pulse unless the crystal is made thin, thus limiting the conversion efficiency. The alternative is to focus the fundamental beam into a gas, but the phase shift accumulated by a Gaussian beam as it propagates through the focus leads to destructive interference of the generated harmonics. This work presents two methods to alleviate this issue through the use of a semi-infinite geometry for third harmonic generation. The first method involves placing a metal septum at the waist such that the laser drills a small pinhole, which in turn disrupts the beam after the waist. The second method uses a very thin septum as a separator for two gases: one with a large third order susceptibility (before the focus), and the other with a small susceptibility (after the focus). Both methods inhibit harmonic generation immediately after the beam waist. Experiments with third harmonic generation lead to increased conversion efficiency and better mode quality, and had the appropriate perturbative behavior. Simulations supported the experimental results and were used to explore limitations on generation. The techniques were extended to fifth harmonic generation. Although an improved spectrum was observed, increased conversion efficiency was not observed in the experiment. Moreover, simulations indicated that fifth harmonic light production is due to wave-mixing, not generation. Finally, simulations with Bessel-like beams are explored as an alternative method for future experiments.
Author: Ekaterina V. Sergan
Publisher:
ISBN:
Category : Bessel functions
Languages : en
Pages : 101
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Book Description
Table top short-pulsed UV lasers are coveted for their usefulness in time-resolved studies of molecular dynamics. However, current wave-mixing and harmonic generation techniques using crystals fail to preserve the short pulse unless the crystal is made thin, thus limiting the conversion efficiency. The alternative is to focus the fundamental beam into a gas, but the phase shift accumulated by a Gaussian beam as it propagates through the focus leads to destructive interference of the generated harmonics. This work presents two methods to alleviate this issue through the use of a semi-infinite geometry for third harmonic generation. The first method involves placing a metal septum at the waist such that the laser drills a small pinhole, which in turn disrupts the beam after the waist. The second method uses a very thin septum as a separator for two gases: one with a large third order susceptibility (before the focus), and the other with a small susceptibility (after the focus). Both methods inhibit harmonic generation immediately after the beam waist. Experiments with third harmonic generation lead to increased conversion efficiency and better mode quality, and had the appropriate perturbative behavior. Simulations supported the experimental results and were used to explore limitations on generation. The techniques were extended to fifth harmonic generation. Although an improved spectrum was observed, increased conversion efficiency was not observed in the experiment. Moreover, simulations indicated that fifth harmonic light production is due to wave-mixing, not generation. Finally, simulations with Bessel-like beams are explored as an alternative method for future experiments.
Author: Rashid A Ganeev
Publisher: Springer
ISBN: 9811001944
Category : Science
Languages : en
Pages : 230
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Book Description
This book offers a review of the use of extended ablation plasmas as nonlinear media for HHG of high-order harmonic generation (HHG). The book describes the different experimental approaches, shows the advantages and limitations regarding HHG efficiency and discusses the particular processes that take place at longer interaction lengths, including propagation and quasi-phase matching effects. It describes the most recent approaches to harmonic generation in the extreme ultraviolet (XUV) range with the use of extended plasma plumes, and how these differ from more commonly-used gas-jet sources. The main focus is on studies using extended plasmas, but some new findings from HHG experiments in narrow plasma plumes are also discussed. It also describes how quasi-phase-matching in modulated plasmas, as demonstrated in recent studies, has revealed different means of tuning enhanced harmonic groups in the XUV region. After an introduction to the fundamental theoretical and experimental aspects of HHG, a review of the most important results of HHG in narrow plasmas is presented, including recent studies of small-sized plasma plumes as emitters of high-order harmonics. In Chapter 2, various findings in the application of extended plasmas for harmonic generation are analyzed. One of the most important applications of extended plasmas, the quasi-phase-matching of generated harmonics, is demonstrated in Chapter 3, including various approaches to the modification of perforated plasma plumes. Chapter 4 depicts the nonlinear optical features of extended plasmas produced on the surfaces of different non-metal materials. Chapter 5 is dedicated to the analysis of new opportunities for extended plasma induced HHG. The advantages of the application of long plasma plumes for HHG, such as resonance enhancement and double-pulse method, are discussed in Chapter 6. Finally, a summary section brings together all of these findings and discuss the perspectives of extended plasma formations for efficient HHG and nonlinear optical plasma spectroscopy. The book will be useful for students and scholars working in this highly multidisciplinary domain involving material science, nonlinear optics and laser spectroscopy. It brings the new researcher to the very frontier of the physics of the interaction between laser and extended plasma; for the expert it will serve as an essential guide and indicate directions for future research.
Author: Rashid A. Ganeev
Publisher: World Scientific
ISBN: 1848169809
Category : Science
Languages : en
Pages : 250
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Book Description
This book represents the first comprehensive treatment of high-order harmonic generation in laser-produced plumes, covering the principles, past and present experimental status and important applications. It shows how this method of frequency conversion of laser radiation towards the extreme ultraviolet range matured over the course of multiple studies and demonstrated new approaches in the generation of strong coherent short-wavelength radiation for various applications. Significant discoveries and pioneering contributions of researchers in this field carried out in various laser scientific centers worldwide are included in this first attempt to describe the important findings in this area of nonlinear spectroscopy. High-Order Harmonic Generation in Laser Plasma Plumes is a self-contained and unified review of the most recent achievements in the field, such as the application of clusters (fullerenes, nanoparticles, nanotubes) for efficient harmonic generation of ultrashort laser pulses in cluster-containing plumes and resonance-induced enhancement of harmonic yield. It can be used as an advanced monograph for researchers and graduate students working in the field of nonlinear spectroscopy. It is also suitable for researchers in laser physics and nonlinear optics who wish to have an overview of the advanced achievements in laser ablation-induced high-order harmonic generation spectroscopy. The carefully presented details of this book will be of value to research devoted to the understanding and control frequency conversion of laser pulses in plasma plumes. The studies described in this book pave the way for the development of a new method of materials studies using the laser ablation-induced high-order harmonic generation spectroscopy, which can exploit the spectral and structural properties of various solid-state materials through their ablation and further propagation of short laser pulse through laser-produced plasma and generation of high-order harmonics.
Author: Rashid A. Ganeev
Publisher: John Wiley & Sons
ISBN: 1119472350
Category : Science
Languages : en
Pages : 371
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Book Description
A comprehensive guide to a new technology for enabling high-performance spectroscopy and laser sources Resonance Enhancement in Laser-Produced Plasmas offers a guide to the most recent findings in the newly emerged field of resonance-enhanced high-order harmonic generation using the laser pulses propagating through the narrow and extended laser-produced plasma plumes. The author—a noted expert in the field—presents an introduction and the theory that underpin the roles of resonances in harmonic generation. The book also contains a review of the most advanced methods of plasma harmonics generation at the conditions of coincidence of some harmonics, autoionizing states, and some ionic transitions possessing strong oscillator strengths. Comprehensive in scope, this text clearly demonstrates the importance of resonance-enhanced nonlinear optical effects leading to formation of efficient sources of coherent extreme ultraviolet radiation that can be practically applied. This important resource: Puts the focuses on novel applications of laser-plasma physics, such as the development of ultrashort-wavelength coherent light sources Details both the theoretical and experimental aspects of higher-order harmonic generation in laser-produced plasmas Contains information on early studies of resonance enhancement of harmonics in metal-ablated plasmas Analyzes the drawbacks of different theories of resonant high order harmonic generation Includes a discussion of the quasi-phase-matching and properties of semiconductor plasmas Written for researchers and students in the fields of physics, materials science, and electrical engineering who are interested in laser physics and optics, Resonance Enhancement in Laser-Produced Plasmas offers an introduction to the topic and covers recent experimental studies of various resonance processes in plasmas leading to enhancement of single harmonic.
Author: Dominik Walter
Publisher:
ISBN:
Category :
Languages : en
Pages : 140
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Book Description
Author: Anna Lena Giesecke
Publisher:
ISBN:
Category :
Languages : en
Pages : 314
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Book Description
Author: Dian Peng
Publisher:
ISBN: 9781392857038
Category : Laser pulses, Ultrashort
Languages : en
Pages : 0
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Book Description
Nonlinear processes of high-order harmonic generation (HHG) produced by ultrashort few-cycle laser pulses possess interesting features which HHG produced by long pulses of many cycles may not have. First, HHG spectra produced by ultrashort pulses are extremely sensitive to the driving pulse waveform, which can be controlled by laser parameters such as carrier-envelope phases (CEPs), time delays or frequency chirps. Second, HHG spectra produced by ultrashort pulses can exhibit broad uneven peaks which are different from usual odd-ordered harmonic peaks that long pulses produce. Based on the high sensitivity on pulse waveform of HHG spectra produced by ultrashort pulses, we investigate for a two-color few-cycle pulse how HHG can be enhanced by the use of time delays or frequency chirps. Both a numerical and an analytic method are employed to calculate HHG spectra from a single H atom. For the time delay case, our results show that a time delay between the two-color, few-cycle pulses can increase the intensity of an HHG spectrum by an order of magnitude (or more) compared to the no-time-delay case at the cost of a reduction in the HHG plateau cutoff energy. For the frequency chirp case, we show how changing signs of chirps in each of the two component few-cycle pulses leads to drastic changes in the HHG spectra. Both time-frequency analyses from the numerical method and a semiclassical interpretation from the analytic method provide clear physical explanations of how HHG spectra are changed by those time delays and chirp signs.Based on the broad uneven peaks in HHG spectra produced by ultrashort pulses, we investigate how the duration of an isolated attosecond pulse can be minimized by carefully selecting frequencies in an HHG spectrum and provide a solution for the attochirp problem in generating attosecond pulses. Specifically, three frequency-selection categories are studied: a single spectral range between cutoffs, a single spectral range across cutoff and a striped-frequency range. Our results show that among all three categories the striped-frequency range produces the shortest and strongest attosecond pulses for a broad HHG spectrum with transform-limited duration.
Author: Dominik Walter
Publisher:
ISBN:
Category :
Languages : en
Pages : 0
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Book Description
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 0
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Book Description
Author: Jean-Claude Diels
Publisher: Elsevier
ISBN: 0080466400
Category : Science
Languages : en
Pages : 675
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Book Description
Ultrashort Laser Pulse Phenomena, Second Edition serves as an introduction to the phenomena of ultra short laser pulses and describes how this technology can be used to examine problems in areas such as electromagnetism, optics, and quantum mechanics. Ultrashort Laser Pulse Phenomena combines theoretical backgrounds and experimental techniques and will serve as a manual on designing and constructing femtosecond ("faster than electronics") systems or experiments from scratch. Beyond the simple optical system, the various sources of ultrashort pulses are presented, again with emphasis on the basic concepts and how they apply to the design of particular sources (dye lasers, solid state lasers, semiconductor lasers, fiber lasers, and sources based on frequency conversion). - Provides an easy to follow guide through "faster than electronics" probing and detection methods - THE manual on designing and constructing femtosecond systems and experiments - Discusses essential technology for applications in micro-machining, femtochemistry, and medical imaging
