Second-harmonic generation in germanosilicate glasses was encoded by coherent superposition of the 810-nm fundamental and the 405-nm second-harmonic light of a femtosecond laser. The difference spectra between the absorption spectra of the glasses before and after preparation were measured. An evident correlation between the induced second-order nonlinearity and the creation of a Ge electron center was observed, suggesting that a band-to-band transition by multiphoton absorption is probably responsible for the photoinduced second-harmonic generation.
© 1999 Optical Society of America
Jinhai Si, Kenji Kitaoka, Jianrong Qiu, Tsuneo Mitsuyu, and Kazuyuki Hirao, "Optically encoded second-harmonic generation in germanosilicate glass by a femtosecond laser," Opt. Lett. 24, 911-913 (1999)