Nonlinear Responses and Optical Properties Modification οf SK3 under Irradiation of Femtosecond Laser Pulses

Abstract

In this paper, the nonlinear responses and optical properties modification in SK3 glass sample are investigated. The nonlinear responses measurements were performed by using of nonlinear transmission monitoring of 200 fs at 800 nm laser pulses. The optical power limiting threshold of the sample is measured to be about 40 mJ/cm 2 . The decrease of transmitted intensity is about 63% compared to the theoretical linear transmission at 270 mJ/cm 2 incident pulse energy. For prediction of the experimental nonlinear behavior results, a theoretical model based on three-photon absorption and absorption of free carriers is presented. By fitting of experimental data with theoretical model, three-photon absorption coefficient and free-carrier absorption cross-section are reported. The photo-induced optical properties modification of the SK3 sample is investigated also. The modifications that appear as darkening are observed below breakdown threshold intensity. To analyses of modified region sizes, the laser pulse energy accumulation model is applied.

Borofloat, BK7 és B270 optikai üvegminták ablációja és tranziens reflexió-növekedésének vizsgálata ultrarövid lézerimpulzusokkal

“…Ezek az eredmények arra utalnak, hogy a háromfotonos abszorpciós együttható anyagspecifikussága mellett intenzitásfüggő viselkedést produkál. Ezt megerősítik azok a kísérleti eredmények is, melyek szerint a nemlineáris abszorpció növekszik a besugárzás intenzitásának növelésével [71][72][73][74][75][76].…”