Chromium- and neodymium-activated gadolinium-scandium-gallium garnet crystal: A new laser active medium

The mechanisms underlying the population of the upper lasing level of neodymium is investigated in order to identify the optimum working conditions for the active medium in various types of lasers. A general method is proposed for calculating the population of the excited state of acceptors interacting with energy donors which allows for non-radiative losses in the acceptor subsystem for the steady-state and pulsed pumping modes for any pumping pulse form. The time evolution of the population of the upper lasing level of 4F(3/2)Nu(3+) in gadolinium-scandium-gallium garnet crystals activated with chromium and neodymium is analyzed, along with the population gain in the 4F(3/2) level of Nd(3+) due to sensitization of Nd(3+) ion luminescence by Cr(3+) ions. The proposed method for calculating the kinetics of the decay of the excied state of acceptors interacting with energy donors is used to find the optimum concentrations of Nd(3+) ions in chromium- and neodymium- activated gadolinium-scandium-gallium garnet crystals for steady-state and impulse modes.