Absorption of thin Al<sub>2</sub>O<sub>3</sub> films was measured at 193 nm with an ArF-laser calorimeter. In addition to the expected high linear absorption coefficient, we found, for the first time to our knowledge, that two-photon absorption and transient color-center formation are nonnegligible loss channels in thin films at 193 nm. The nonlinear absorption coefficient is of the order of several times 10<sup>−4</sup> cm/W.
© 2000 Optical Society of America
Oliver Apel, Klaus Mann, Alfons Zoeller, Rainer Goetzelmann, and Eric Eva, "Nonlinear Absorption of Thin Al2O3 Films at 193 nm," Appl. Opt. 39, 3165-3169 (2000)