Self-deflection of screening-photovoltaic spatial solitons in biased photovoltaic photorefractive crystals

The self-deflection of a solitary wave arising from diffusion effects in a biased photovoltaic photorefractive crystal has been systematically investi gated by employing numerical techniques. Adjusting both strength and polari ty of the biased field can change the bending angle of the screening-photov oltaic (SP) soliton, and it is more effective by adjusting the polarity tha n by adjusting the strength. The stronger the input intensity is, the large r the bending angle is for a dark SP soliton, whereas the bending angle ten ds to decrease for very weak input intensity as well as for a very strong o ne, and has a larger value between these two regimes for a bright SP solito n. The dark SP soliton deflects left, whereas the bright one deflects right . The self-bending process of a SP soliton still occurs in a lossy crystal. If the input optical beam is a Gauss beam, whether it can evolve into a st able SP bright soliton or not in the crystal, it will bend with distance.