Page 389 - High Power Laser Handbook

358 So l i d - S t at e La s e r s The National Ignition Facility Laser 359

We have structured this chapter as follows: Section 14.2 summarizes
the development history of high-energy solid-state lasers that are
intended to probe thermonuclear fusion physics. Section 14.3 provides
a brief overview of the NIF facility and laser design. This is followed
in Secs. 14.4 to 14.6 with a detailed description of each major laser
subsystem, along with performance validation experiments carried
out in 2006. (These sections are largely excerpts from a review article
1
we wrote. ) These experiments demonstrated that the NIF laser
would meet both its original design specifications, as laid out in 1994,
and the ignition campaign requirements that evolved as progress in
target physics modeling, fabrication, and understanding was made.
The results presented in Secs. 14.4 to 14.6 cover the predicted and
measured performance of the laser obtained during the final stages of
the activation or commissioning of the first of NIF’s 24 bundles. The
performance envelope of the laser’s 1ω portion was explored by a
series of shots at progressively higher 1ω energies. In Sec. 14.4, we
compare model predictions of each of the eight beamlines with
measured energies, report the shot-to-shot energy reproducibility,
and show the 1ω power and energy operating envelopes for NIF.
Section 14.5 details how a shaped pulse is created, diagnosed, and
amplified as it traverses the NIF laser and how its frequency is con-
verted to the third harmonic by nonlinear crystals in the final optics
assembly (FOA). It also describes a series of laser shots that validated
NIF’s capability of meeting its energy, power, and temporal contrast
design goals. These performance qualification (PQ) shots were taken
with an entire bundle operating at 1ω. Section 14.6 describes the addi-
tion of focal spot beam conditioning to the laser. It also details the
generation of two shaped pulses that had all three beam-conditioning
methods applied and that simultaneously generated the single-beam
3ω powers and energies planned for the first ignition campaigns on
NIF. We conclude in Sec. 14.7 with a description of the present state as
the completed machine carries out initial plasma physics and target
compression experiments preparatory to a fusion ignition campaign
in late 2010 to mid-2012.

14.2 Historical Background
The laser era was born on May 16, 1960, when Theodore Maiman of
Hughes Research Laboratory first exposed a 1-cm ruby crystal, pol-
ished on two parallel faces, to a high-power pulsed flash lamp and
2
observed a marked narrowing of the emission spectrum. Within days
of the publication of this event, Stirling Colgate, Ray Kidder, and John
Nuckolls of the Livermore branch of the Lawrence Radiation Labora-
tory in Livermore (now the Lawrence Livermore National Laboratory
[LLNL]) separately proposed investigating whether devices based on
this phenomenon could be used to drive thermonuclear fusion in a