A 40 % slope efficiency from a pulsed Er3+LiYF4 is demonstrated under cw Ti:sapphire pumping. This value clearly exceeds the Stokes limit of 35 % due to energy recycling fiom lower to upper laser level. With reduction of the pump-pulse duration a decrease of the slope efficiency and an increase of the threshold is experimentally observed and confirmed by a computer simulation. An approximate function following an exponential law can be used to describe the dependence of the slope efficiency on the pump-pulse duration.
© 1996 Optical Society of AmericaPDF Article