Photoelectric phenomena on the surface of a transparent dielectric subjected to laser light

An investigation was made of the photocurrent which appeared on the surface of a transparent dielectric subjected to laser illumination whose energy density was several times lower than the threshold value necessary for the generation of a spark. "Fatigue" of the photocurrent was observed when the same region of the surface was illuminated with a beam of constant energy density. However, the photocurrent recovered when the laser energy density was increased. Photoelectric emission was observed. The photocurrent after the first pulse depended strongly on the surface treatment and, in this sense, was correlated with the damage threshold.