Phase-matching Optimization of Laser High-order Harmonics Generated in a Gas Cell PDF Download
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Author: Julia Robin Miller Sutherland
Publisher:
ISBN:
Category : Electronic dissertations
Languages : en
Pages : 104
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Book Description
Ten-millijoule, thirty-five femtosecond, 800 nm (4̃0 nm bandwidth) laser pulses are used to study high-order harmonic generation in helium- and neon-filled gas cells of various lengths. Harmonic orders in the range of 50 to 100 are investigated. A semi-infinite cell geometry produces brighter harmonics than cells of sub-centimeter length. In the semi-infinite geometry, the gas occupies the region from the focusing lens to a thin exit foil near the laser focus. Counter-propagating light is used to directly probe where the high harmonics are generated within the laser focus and to investigate phase matching. The phase matching under optimized harmonic generation conditions was found to be unexpectedly good with phase zones many millimeters long.
Author: Julia Robin Miller Sutherland
Publisher:
ISBN:
Category : Electronic dissertations
Languages : en
Pages : 104
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Book Description
Ten-millijoule, thirty-five femtosecond, 800 nm (4̃0 nm bandwidth) laser pulses are used to study high-order harmonic generation in helium- and neon-filled gas cells of various lengths. Harmonic orders in the range of 50 to 100 are investigated. A semi-infinite cell geometry produces brighter harmonics than cells of sub-centimeter length. In the semi-infinite geometry, the gas occupies the region from the focusing lens to a thin exit foil near the laser focus. Counter-propagating light is used to directly probe where the high harmonics are generated within the laser focus and to investigate phase matching. The phase matching under optimized harmonic generation conditions was found to be unexpectedly good with phase zones many millimeters long.
Author: Dinh Ba Khuong
Publisher: Nova Science Publishers
ISBN: 9781626181281
Category : X-ray lasers
Languages : en
Pages : 0
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Book Description
High order harmonic generation (HHG) produced by the interaction of an intense laser pulse and a gas medium can provide a table top scale coherent radiation source in the short wavelength range from the extreme ultraviolet to the soft x-ray region. This book presents a study based on high order harmonic generation in a semi-infinite gas cell. Two novel schemes are presented which have been used to enhance the quality of the HHG source including the conversion efficiency, the coherence, and the cut-off photon energy. This book focuses on the phase matching of the non-linear conversion process which is the main limitation to the quality of the HHG source. In the first scheme, a combination of lens and axicon is used to create a Bessel Gaussian beam instead of only a Gaussian beam and the presence of a new geometrical phase mismatch term is demonstrated. This allows us to compensate for the phase mismatch and thus to enhance the phase matching condition. In the second scheme, the phase matching is controlled by a means of an off-axis beam. When the phase mismatch is varied, mainly due to a change in the dipole phase term, the harmonic emission can be destroyed or enhanced. This technique provides the possibility to generate very high harmonic photon energies.
Author: Kelly Smith
Publisher:
ISBN:
Category : Harmonics (Electric waves)
Languages : en
Pages : 64
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Book Description
Author: Sergei Leonidovich Voronov
Publisher:
ISBN:
Category : Electronic dissertations
Languages : en
Pages : 142
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Book Description
A new high-power laser system with higher pulse energy has been constructed to further investigate quasi phase matching of high-order harmonics generated in difficult-to-ionize atomic gases (e.g., neon as opposed to argon). The new system can also be used to study harmonic generation in ions. A new counter-propagating beam produces a train of 5 pulses with regulated timing. In preliminary tests, the new system has produced high harmonics up to the 65th order in neon. This should increase with additional adjustments to the laser system. The high-order harmonics have also demonstrated to be useful for polarized reflectometry measurements of optical surfaces in the extreme ultraviolet (EUV) wavelength range.
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: John Joseph Macklin
Publisher:
ISBN:
Category :
Languages : en
Pages : 264
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Book Description
Author: C. D. Lin
Publisher: Cambridge University Press
ISBN: 1108195660
Category : Science
Languages : en
Pages : 420
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Book Description
Probing and controlling electrons and nuclei in matter at the attosecond timescale became possible with the generation of attosecond pulses by few-cycle intense lasers, and has revolutionized our understanding of atomic structure and molecular processes. This book provides an intuitive approach to this emerging field, utilizing simplified models to develop a clear understanding of how matter interacts with attosecond pulses of light. An introductory chapter outlines the structure of atoms and molecules and the properties of a focused laser beam. Detailed discussion of the fundamental theory of attosecond and strong-field physics follows, including the molecular tunnelling ionization model (MO-ADK theory), the quantitative rescattering (QRS) model, and the laser induced electronic diffraction (LIED) theory for probing the change of atomic configurations in a molecule. Highlighting the cutting-edge developments in attosecond and strong field physics, and identifying future opportunities and challenges, this self-contained text is invaluable for students and researchers in the field.
Author: J Zhang
Publisher: CRC Press
ISBN: 9780750310109
Category : Technology & Engineering
Languages : en
Pages : 736
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Book Description
X-Ray Lasers 2004 comprises invited, contributed, and poster papers presented at the 9th International Conference on X-Ray Lasers (ICXRL2004) held in Beijing in May 2004. Some 120 participants from 13 countries and regions met in Beijing to compare results and exchange views on future developments in x-ray lasers and related fields. The book covers the following topics: overviews of x-ray lasers research, collisionally pumped x-ray lasers, capillary discharge-pumped x-ray lasers, OFI and photo-pumped x-ray lasers, high-order harmonics XUV radiation, grazing incidence pumping x-ray lasers, theory and simulations of x-ray lasers and plasma media, free-electron lasers and accelerator-based x-ray sources, alternative pumping schemes for x-ray lasers, applications of x-ray lasers and other bright x-ray sources, x-ray optics and instrumentation, investigations of x-ray laser media, and developments of x-ray laser drivers. X-Ray Lasers 2004 provides not only an overview and an up-to-date progress report on this fast moving field, but also important reference material on which future work can be built.
Author: Kimberly Susan Budil
Publisher:
ISBN:
Category :
Languages : en
Pages : 274
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Book Description
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :
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Book Description
Abstract: With the development of laser technologies, multi-color light-field synthesis with complete amplitude and phase control would make it possible to generate arbitrary optical waveforms. A practical optimization algorithm is needed to generate such a waveform in order to control strong-field processes. We review some recent theoretical works of the optimization of amplitudes and phases of multi-color lasers to modify the single-atom high-order harmonic generation based on genetic algorithm. By choosing different fitness criteria, we demonstrate that: (i) harmonic yields can be enhanced by 10 to 100 times, (ii) harmonic cutoff energy can be substantially extended, (iii) specific harmonic orders can be selectively enhanced, and (iv) single attosecond pulses can be efficiently generated. The possibility of optimizing macroscopic conditions for the improved phase matching and low divergence of high harmonics is also discussed. The waveform control and optimization are expected to be new drivers for the next wave of breakthrough in the strong-field physics in the coming years.
