Giant increase of the second harmonic radiation's absorption during optical poling of oxide glass

Abstract

A giant reversible growth (≥ 10³ times) of the absorption of second harmonic radiation by optical poling of oxide glass was discovered. The observed absorption exerts an influence on the optical poling process and leads to a restriction of the maximum value of the photoinduced second harmonic generation in oxide glass. A theoretical model of the observed phenomenon is given. The growth of absorption is considered as a result of special anharmonic electron-phonon interactions caused by photoinduced electrostricted phonons. Exploration of the total absorption indicates that the effects of photodarkening do not play a key role in the observed phenomena.