Abstract

Lead silicate glasses were found to be promising materials for photoinduced second-harmonic generation (SHG).^1,2 It was shown that macroscopic charge separation due to the coherent photovoltaic effect is responsible for photoinduced SHG in these glasses.² As a result of charge separation and trapping in the non-illuminated region, there will be a strong electrostatic field E = −j_ph/σ and, consequently, a second- order susceptibility χ⁽²⁾ = χ⁽³⁾E, where j_ph is the coherent photocurrent, σ is the photoconductivity which is dependent on the fundamental (and/or second-harmonic, etc.) wavelength, and χ⁽³⁾ is the third-order polarizability. Despite this phenomenological understanding the origin of the photoconductivity during SHG preparation is not understood and this is the subject of our present investigation.

© 1994 Optical Society of America