Holographic screening-photovoltaic solitons in biased photovoltaic-photorefractive crystals with two-wave mixing

¹ State Key Laboratory of Laser Technology Huazhong University of Science and Technology Wuhan, 430074, PRC
² Optisches Institut, Technische Universitaet Berlin Strasse des 17 Juni, 135, D-10623 Berlin, Germany

Corresponding author: jsliu4508@vip.sina.com

Received: 18 September 2003
Accepted: 16 December 2003

Abstract

We propose a new kind of optical spatial solitons in biased photovoltaic-photorefractive materials when the self-trapping beam couples coherently with a pump beam by codirectional degenerate two-wave mixing. Such solitons are a result of double balance, i.e., loss is balanced by gain provided by the pump beam via two-wave mixing, and diffraction is balanced by nonlinearity that is due to the spatially nonuniform screening of the applied field, the photovoltaic effect, and the periodic modulation of the refractive index via two-wave mixing. These solitons possess some unique properties, are stable relative to small perturbations, and can become screening-photovoltaic solitons if the pump beam is switched to a background illumination.