Published online by Cambridge University Press: 09 March 2009
A γ-ray laser would stimulate the emission of radiation of wavelengths below 1 Å from excited states of nuclei. However, the anticipation of a need for high pump powers tended to discourage early research and the difficulties in demonstrating a device were first assumed to be insurmountable. Over the past decade, advances in pulsed-power technology have changed these perceptions and studies have built a strong momentum. A nuclear analog of the ruby laser has been proposed and many of the component steps for pumping the nuclei have been demonstrated experimentally. A quantitative model based upon the new data and concepts has shown the γ-ray laser to be feasible if some real isotope has its properties sufficiently close to the ideals modeled. The greatest positive impact upon feasibility has come from the discovery of giant resonances for pumping nuclei that greatly reduce the levels of pump power needed.