Visible and Near-Infrared Direct Nuclear Pumped Lasers

In this paper an attempt has been made to summarize the current experimental data on direct nuclear pumped (DNP) lasers Operating in the visible and near-infrared ranges. The first laser of this type was started in the USSR in 1979. It simultaneously generated two green lines of CdII ion: 533.7 nm and 537.8 nm. At this time, nuclear pumped lasing has been obtained in visible and near-IR ranges with many transitions of CdII, ZnII, NeI and CdI. The existing DNP-lasers operate in the quasi-continuous mode in the wavelength range from 441.6 nm to 853.0 nm. The volumes of active media of such lasers are similar to 500 - 6000 cm(3); the specific power reaches 1 W/cm(3). The active media are mixtures of inert gases or metal vapors with inert gases. The author's main emphasis is placed on metal-vapor DNP-lasers which seem to be promising from the viewpoint of possible improvement of gains of active media, increase of power and efficiency, and reduction of threshold flux densities of pumping by thermal neutrons. A great deal of attention is paid to spectroscopic characteristics of low temperature plasmas produced by nuclear particles because this field has provided the basis for development of visible DNP-lasers.