Excitation energies and transition rates in ytterbiumlike ions

Anatoly N. Soldatov, N. A. Yudin, Anna V. Vasileva +4 more

The frequency and energy parameters of self-contained strontium ion laser ( λ = 1.033 and 1.091 μm) are studied upon excitation by an additional pulse before each excitation pulse. The kinetics of processes in the active medium of this laser is numerically simulated. It is shown that the pulse repetition rate of the self-contained strontium laser can achieve ∼1 MHz. It is found that the laser pulse energy in the first pulse and the average output power and efficiency increase in a certain range of time delays between the additional and excitation pulses, which is caused by the significant prepulse concentration of strontium ions which had no time to recombine. The outlook for the application of pulse trains to excite self-contained IR transitions in strontium ions is shown.

Peng Zhang, A. Dalgarno, Robin Côté

І. І. Бондар, M. I. Dudich, В. В. Суран +1 more

Alexander G. Murzin, D. S. Prilezhaev, Victor A. Fromzel

An analysis is made of some processes that occur under conditions of accumulation of population inversion due to the 4 I 13/2 – 4 I 15/2 resonant transition in Er 3+ ions in ytterbium–erbium (Yb–Er) glasses of various compositions. Methods of measuring the parameters of direct and reverse excitation energy transfer between Er 3+ and Yb 3+ ions are also studied. It is found that, under certain conditions achieved in practice, appreciable bleaching of the medium should be observed at the frequency of the pump radiation, particularly under conditions of high-intensity reverse transfer of excitation energy from Er 3+ to Yb 3+ ions. This is typical of glasses having a low rate of intracenter relaxation of Er 3+ ions. It is also shown that nonsteady-state rate equations that assume a linear relationship between the rate of interionic transfer and the ground state population of the acceptor consistently describe the energy characteristics of the excitation processes of Yb–Er glasses. In this case, it is not necessary to introduce in the calculation model additional excitation losses that increase nonlinearly with the pump radiation.

Takashi Kushida

Calculations made of the rates for several processes involving interactions between rare earth ions in crystals, such as resonance energy transfer, cooperative excitation transfer and cooperative optical transitions. These processes are assumed to originate from the electric multipole interactions between the ions concerned. A tensor operator method is employed in order to take account of the individual characters of the energy levels involved in the transition. Evaluation of the typical transition probability is also made on the lowest-order parity-allowed processes in nearest neighbour ions. The rates for the resonance transfer and cooperative transfer processes thus estimated are much smaller than those obtained by Miyakawa and Dexter.

Nan Yu, Lute Maleki