Excited-state absorption spectroscopy of<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msup><mml:mrow><mml:mi mathvariant="normal">Er</mml:mi></mml:mrow><mml:mrow><mml:mn>3</mml:mn><mml:mo>+</mml:mo></mml:mrow></mml:msup></mml:mrow></mml:math>-doped<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">Y</mml:mi></mml:mrow><mml:mrow><mml:mn>3</mml:mn></mml:mrow></mml:msub></mml:mrow><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">Al</mml:mi></mml:mrow><mml:mrow><mml:mn>5</mml:mn></mml:mrow></mml:msub></mml:mrow><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">O</mml:mi></mml:mrow><mml:mrow><mml:mn>12</mml:mn></mml:mrow></mml:msub></mml:mrow><mml:mrow><mml:msub><mml:mrow><mml:mo>,</mml:mo><mml:mi mathvariant="normal"> </mml:mi><mml:mi mathvariant="normal">YVO</mml:mi></mml:mrow><mml:mrow><mml:mn>4</mml:mn></mml:mrow></mml:msub></mml:mrow><mml:mo>,</mml:mo></mml:math>and phosphate glass

The spectra of excited-state absorption (ESA) and stimulated-emission (SE) cross sections of ${\mathrm{Er}}^{3+}$ in ${\mathrm{Y}}_{3}{\mathrm{Al}}_{5}{\mathrm{O}}_{12},$ ${\mathrm{YVO}}_{4},$ and phosphate glass have been registered between 0.4 and 3 \ensuremath{\mu}m with a pump and probe technique. The experimental setup, based on the use of cw light sources, is described in detail. The incidence of ESA on the laser properties of these ${\mathrm{Er}}^{3+}$-doped oxide hosts is evaluated particularly around 0.55, 1.6, and 2.8 \ensuremath{\mu}m, corresponding to the ${}^{4}{\mathrm{S}}_{3/2}{\ensuremath{\rightarrow}}^{4}{\mathrm{I}}_{15/2},$ ${}^{4}{\mathrm{I}}_{13/2}{\ensuremath{\rightarrow}}^{4}{\mathrm{I}}_{15/2},$ and ${}^{4}{\mathrm{I}}_{11/2}{\ensuremath{\rightarrow}}^{4}{\mathrm{I}}_{13/2}$ laser transitions, respectively. The migration $[{(}^{4}{\mathrm{I}}_{13/2}{,}^{4}{\mathrm{I}}_{15/2}{)\ensuremath{\rightarrow}(}^{4}{\mathrm{I}}_{15/2}{,}^{4}{\mathrm{I}}_{13/2})]$ and up-conversion $[{(}^{4}{\mathrm{I}}_{13/2}{,}^{4}{\mathrm{I}}_{13/2}{)\ensuremath{\rightarrow}(}^{4}{\mathrm{I}}_{9/2}{,}^{4}{\mathrm{I}}_{15/2})]$ energy transfers involved in some laser operations are analyzed by deducing the energy-transfer microparameters ${C}_{\mathrm{DD}}$ and ${C}_{\mathrm{DA}}$ from ESA and SE measurements. The Judd-Ofelt analysis, usually applied from the ground-state manifold, is then used to evaluate the ESA integrated cross sections and these calculated cross sections are found equal to the measured ones within about 20%.

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