Laser photolysis as applied to the determination of the two-photon absorption cross section of trans-stilbene

The two-photon absorption (TPA) cross section of an ethanol solution of trans-stilbene exposed to radiation of the second harmonic of a Nd:YAG laser (532 nm) of nanosecond duration has been determined using the method based on the measurement of the photodecomposition of trans-stilbene molecules, characterized by a low photostability. The measured TPA cross section of trans-stilbene in ethanol amounts to 25 5 GM, and the photodecomposition quantum yield determined upon excitation by radiation of the fourth harmonic of the Nd:YAG laser (266 nm) is found to be gamma = 0.10 +/- 0.01. The obtained value of the TPA cross section has been compared with the experimental and theoretical data of other authors. The method of photodecomposition can be successfully used for the experimental determination of the TPA cross section of compounds unstable under the photoexcitation such as photochromic molecules, biological objects, and radical photoinitiators.