Investigation of the spectral-luminescent properties of laser media based on double molybdate crystals doped with erbium, ytterbium, europium and thulium ions

  • Руководитель: Anatoly V. Fedorov

Grant RFBR 19-32-90199.

Responsible researcher: Anna A. Volokitina.

The project is devoted to the study of the spectral-luminescent properties of double molybdate crystals KY(MoO4)2, doped with trivalent rare-earth ions (Er3+, Yb3+, Eu3+, Tm3+). To date, relatively few publications have been devoted to the detailed study of the spectroscopic properties of such crystals as an active laser media. It was shown that such crystals allow for high doping concentrations, have large values of absorption and stimulated-emission cross-sections, and exhibit a strong anisotropy of spectral-luminescent properties in a polarized light, which is necessary for lasing. Due to the structural features of double molybdate crystals, they are attractive for the fabrication of thin-film lasers. In the framework of this project, it is planned to study for the first time the spectral-luminescent properties of new crystals, doped with rare-earth ions. It will allow to determine the main spectroscopic characteristics for the effective lasing.

At the first stage of the project, the following main results were obtained:

A comprehensive study of the anisotropy of the spectral-luminescent and lasing properties of Tm:KY(MoO4)2 in polarized light was carried out. The Raman spectra were investigated. The absorption cross-section, stimulated-emission cross-section and gain cross-section were calculated. The maximum stimulated-emission cross-section for the 3F43H6 transition is 2.70×10-20 cm2 at 1856 nm. The lifetime of the 3F4 state is 2.29 ns. Continuous-wave diode-pump laser operation was achieved in thin films and plates of  Tm:KY(MoO4)2 for the first time. A maximum of output power is 0.88 W at 1.9 μm with a slope efficiency of 65.8%. In the framework of the study, an Yb:KY(MoO4)2 crystal was investigated. The maximum of the stimulated-emission cross-section of the Yb3+ ions is 3.70×10-20 cm2 at  1008 nm, with bandwidth = 37 nm for the light polarization E ? b. Continuous-wave microchip laser generated a maximum output power of 0.81 W at 1021-1044 nm with a slope efficiency of 76.4% and linear polarization.

The results were published in the following papers:

1. Volokitina A.A., Loiko P., Pavlyuk A., Serres J.M., Slimi S., Salem E., Sole R., Baranov M.A., Kifle E., Aguilo M., Diaz F., Griebner U., Petrov V., Mateos X. Efficient laser operation in cleaved single-crystal plates of Yb:KY(MoO4)2: A novel molybdate compound // Proceedings of SPIE - 2020, Vol. 11357, pp. 113571T.

2. Volokitina A.A., Loiko P.A., Pavlyuk A.A., Slimi S., Sole R., Salem E., Kifle E., Serres J.M., Griebner U., Petrov V., Aguilo M., Diaz F., Mateos X. Laser operation of cleaved single-crystal plates and films of Tm:KY(MoO4)2 // Optics express - 2020, Vol. 28, No. 7, pp. 9039-9048.