Large photosensitivity in lead-silicate glasses

Strong, permanent surface-relief and refractive index gratings are written in lead-silicate glasses by irradiation with the output of a pulsed KrF exc imer laser (248 nm) through a phase mask. Diffraction efficiencies as high as 10% are obtained. The diffraction efficiency of the refractive index gra ting after removal of the surface-relief grating shows that a very large ph otoinduced refractive index change (Delta n(0) = 0.09+/-0.02) is obtained. (C) 1999 American Institute of Physics. [S0003-6951(99)03815-2].