Page 218 - High Power Laser Handbook

CHAPTER 8

Zigzag Slab Lasers

Hagop Injeyan
Technical Fellow, Northrop Grumman Aerospace Systems,
Redondo Beach, California

Gregory D. Goodno
Senior Scientist, Northrop Grumman Aerospace Systems,
Redondo Beach, California

8.1 Introduction

The invention of zigzag slabs in the early 1970s by Bill Martin and Joe
1
Chernock launched a new paradigm in the development of solid-
state lasers (SSLs). The idea of propagating laser beams in a direction
that averages the temperature gradients in the gain medium has been
the cornerstone of power scaling of SSLs, be it in the form of thin
disks, zigzag slabs, or Brewster-plate amplifiers. Although zigzag
slabs have been the most common architecture for SSL power scaling
in the past 15 years, there has been significant evolution in the imple-
mentation of zigzag slabs by numerous groups. This chapter reviews
the principles of zigzag slab propagation, its scaling laws, and vari-
ous adaptations of this approach to optimize performance.

8.2 Zigzag Slab Principle and Advantages

8.2.1 Zigzag Geometry
The zigzag slab geometry is shown schematically in Fig. 8.1. Typically,
a rectangular cross-section slab is cut to have angled input faces and
polished sides. The slab is, in general, cooled from the polished faces.
The laser beam is injected into the slab so that it will allow the beam
to make multiple total internal reflections (TIRs) from the polished
sides as it propagates down the slab. The main purpose of the zigzag

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