We show theoretically and experimentally that the photovoltaic nonlinearity that gives rise to spatial solitons can be switched from self-defocusing to self-focusing (or vice versa) by use of background illumination. This raises the possibility of bright photovoltaic solitons in LiNbO<sub>3</sub> .
© 1998 Optical Society of America
Charalambos Anastassiou, Ming-feng Shih, Matthew Mitchell, Zhigang Chen, and Mordechai Segev, "Optically induced photovoltaic self-defocusing-to-self-focusing transition," Opt. Lett. 23, 924-926 (1998)