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.
