Abstract.
The differential absorption spectra of Co2+: MgAl2O4 (MALO) crystal were studied with a picosecond pump-probe technique under excitation of the 4A2→4T1(4P) and 4A2→4T1(4F) transitions of the tetrahedral Co2+ ion. The difference spectra of stimulated emission (SE) and excited state absorption (ESA) were derived from the measured differential absorption spectra. The 4T1(4P)→4A2 SE band around 660 nm was observed. The ESA bands were assigned to the 4T2→4T1(4P) transition and to transitions from the thermally populated 2E(2G) excited state to doublet levels arising from the 2F free-ion level of the tetrahedrally coordinated Co2+ ion. Absorption saturation measurements were performed at 1.34 μm and 1.54 μm. Passive Q-switching of 1.34-μm Nd3+:YAlO3 and 1.54-μm Er3+:glass lasers was realized using the Co2+:MALO crystal as saturable absorber. The Q-switched laser pulses of 38 ns (110 ns) in duration and up to 2.7 mJ (10 mJ) in energy at 1.54 μm (1.34 μm) were obtained.
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Received: 3 March 1999 / Revised version: 30 June 1999 / Published online: 30 November 1999
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Yumashev, K., Denisov, I., Posnov, N. et al. Nonlinear absorption properties of Co2+:MgAl2O4 crystal . Appl Phys B 70, 179–184 (2000). https://doi.org/10.1007/s003400050029
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DOI: https://doi.org/10.1007/s003400050029