Self-pulsing in Tm-doped<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mi>YAlO</mml:mi><mml:mn>3</mml:mn></mml:msub></mml:math>lasers: Excited-state absorption and chaos

Tm:$\mathrm{YAlO}{}_{3}$ lasers suffer from self-pulsing. A four-level rate equation analysis suggested that the self-pulsing could be due to excited-state absorption. We report a measurement of the cross section for this absorption and show that it is too small to be the sole cause of the self-pulsing. We propose nonlinear dynamical chaos as an alternative explanation and present a chaos analysis of the output of a cw-pumped Tm:$\mathrm{YAlO}{}_{3}$ laser, including experimental evidence of chaos.