Direct pumping of the upper Nd laser level at 885-nm ( rather than at the more traditional broad 808-nm band ) offers the potential of improved performance through a reduction in the lasing quantum defect, thereby improving system efficiency, reducing cooling requirements, and enabling further TEM00 power scaling.
12.
By introducing the quantum defect " d " as an empirical parameter, the energy levels of a generic atom were well approximated by the formula E =-1 / ( n + d ) ^ 2, in the sense that one could reproduce fairly well the observed transitions levels observed in the X-ray region ( for example, see the empirical discussion and derivation in Moseley's law ).
