**1. Introduction**

Direct conversion of nuclear energy into light energy is of great interest as it provides for application of compact and energy-intensive nuclear energy sources to create high-power generators of coherent and incoherent optical radiation. Nuclear energy pumping into active laser medium was first proposed with the appearance of first lasers [1, 2]. At present, the research on nuclear-pumped lasers (NPL) has progressed to the stage where design and engineering developments of continuous and pulse nuclear laser equipment for various purposes have become possible, that is integrated units based on nuclear engineering and physics, quantum electronics, physics of low-temperature plasma, optics, gas dynamics, and other areas of science and technology [3].

© 2016 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Nuclear-pumped lasers have potential in a wide range of applications, especially in cases requiring high-power and compact lasers to be placed on autonomous remote facilities. The most promising areas of nuclear-pumped laser application are as follows: laser thermonu‐ clearfusion, long-distance transmission ofradiant energy and information, rocketlaser engine, laser isotope separation and photochemistry, stratospheric ozone layer recovery, and space junk removal. Considerable interest in this area research is also associated with significant difference between the mechanisms of level population during nuclear pumping and population processes in conventional gas-discharge lasers. Application of nuclear energy for active laser medium pumping can be considered not as the way to create high-power laser, but as the way to obtain energy from nuclear reactor. This necessitates consideration of fundamentally new equipment—a reactor laser designed to spatially combine nuclear laser active medium and nuclear reactor core. This approach opens up opportunity to generate qualitatively new energy.

Attempts to achieve laser action during pumping of condensed media with nuclear radia‐ tion did not yield positive results. The main obstacle on the road of creating condensed media NPLs is their radiation damage: radiation defects of crystal lattice in solid-state laser, radiol‐ ysis, and gas bulb generation on the tracks of nuclear particles in liquid lasers. Presently known gas NPLs [3] radiate in spectral range 391–5600 nm in about 50 atomic transitions of Xe, Ar, Kr, Ne, C, N, Cl, O, I, Hg; Cd+ , Zn+ , Hg+ ions, CO molecules, and N2 + molecular ion.
