Page 25 - High Power Laser Handbook

xxiv Intro d uction

average powers, pulse energy, and shortest pulse widths. This interest,
in turn, has enabled an enormous variety of applications in materials
processing, inertial fusion, defense, spectroscopy, and high-field physics
research.
The SSL part begins with a short introduction (Chap. 7), pro-
viding a broad overview of high-power SSLs and their unique fea-
tures. This chapter is followed by a discussion of CW power-scalable,
zigzag slab lasers in Chaps. 8 and 9. The other primary CW-scalable
SSL geometry—the thin-disk laser—is described in Chap. 10. Chapter 11
discusses the concept of the heat-capacity laser, an out-of-the-box
approach to power scaling that is relevant to military applications
and that allows operation in multisecond “burst” modes. Chapter 12
introduces ultrafast SSLs, in which the design imperatives for gen-
erating short laser pulses must be balanced against those arising
from average power (pulse repetition rate) scaling. Chapter 13 explores
this balance in detail by describing the capabilities of the thin-disk
geometry toward high-repetition-rate, ultrafast pulses. Finally,
Chap. 14 reviews the recently completed National Ignition Facility
laser for fusion energy research, which represents the most elabo-
rate and highest pulse energy laser system built to date.
The next part (Chaps. 15–18) covers the fastest-evolving high-
power technology of the past few years—fiber lasers. Fibers can be
regarded as a specialized subset of SSLs; however, due to their remark-
able geometric properties of light guidance and heat removal, they
provide a unique technology platform for power scaling and packaging
that warrants a full part of their own. Chapter 15 provides a thorough
introduction to fiber lasers, from the fundamental nature of light guid-
ance and modes in fiber to the various types of fibers most commonly
used. It also introduces the nonlinear effects that limit further scaling of
their output power. In Chap. 16, these nonlinear limits are explored in
greater detail as they pertain to the generation of high peak power di-
rectly in fiber. Chapter 17 extends this discussion of peak power scaling
to ultrafast chirped pulse amplifiers, in which the pulse spectral fidelity
plays a critical role toward short pulse generation. Finally, Chap. 18
reviews the state of the art in high-average (CW) power fiber laser per-
formance and engineering, as well as gives an introduction to common
industrial and defense applications.
This book concludes with Chap. 19, which reviews various methods
for beam combining. Combining many lasers in parallel allows beam-
combined systems to achieve many times the performance of any single
laser. A number of state-of-the-art demonstrations of spatial brightness
or pulse energy has resulted from the implementation of beam-
combining methods. Although beam combining is not a laser techno logy
per se, it is assuming greater importance as underlying laser technolo-
gies reach maturity without satisfying the demand for high-spatial
bright ness, which is predominantly driven by defense applications.