Page 388 - High Power Laser Handbook

CHAPTER 14

The National Ignition

Facility Laser

High-Pulse Energy Fusion Laser

Richard A. Sacks
Senior Scientist and Technical Lead, ICF and HED Science
Program (NIF), Lawrence Livermore National Laboratory,
Livermore, California

Christopher A. Haynam
Associate Program Leader, ICF and HED Science Program (NIF),
Lawrence Livermore National Laboratory, Livermore, California

14.1 Introduction
The 192-beam National Ignition Facility (NIF) laser is the world’s
largest, most complex optical system. To meet its goal of achieving
energy gain (ignition) in a deuterium-tritium (DT) nuclear fusion
target, laser design criteria include the ability to generate pulses of up
to 1.8 megajoules (MJ) total energy, with peak power as high as 500
terawatts (TW) and temporal pulse shapes spanning 2 orders of mag-
nitude at the third harmonic (351 nm or 3ω) of the laser wavelength.
The focal spot fluence distribution of these pulses is carefully con-
trolled through a combination of special optics in the 1ω (1053-nm)
portion of the laser (continuous phase plates), smoothing by spectral
dispersion (SSD), and overlapping of multiple beams with orthogo-
nal polarization (polarization smoothing). The NIF laser has been
successfully tested and verified to meet its laser performance design
criteria, as well as the temporal pulse shaping, focal spot condition-
ing, and peak power requirements for two candidate indirect-drive
ignition designs.

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