Enhanced photoinduced chi((2)) in gamma-ray-irradiated bulk glass.

Gamma-ray-irradiated light-flint silicate bulk glass (Schott Glass LF5), which contains a large amount of lead oxide, displays enhanced photoinduced quasi-phase-matched second-harmonic generation (PSHG), whereas nonirradiated glass under the same experimental conditions does not generate this nonlinear effect. The dependence of the efficiency of PSHG on the amount of gamma radiation (up to 530 krad) is experimentally studied, as is the role of thermal recovery (bleaching) of the color centers as a result of seeding with the second harmonic. The effect of long-term fading is studied with a sample that was irradiated 8 years ago. Gamma irradiation of boron-crown silicate glass (BK7) does not show this enhancement.