Nonlinear optical beam propagation and solitons in photorefractive media
The advent of nonlinear optics, mainly due to the work of Bloembergen and coworkers at the beginning of the '60, has opened the way to a number of fundamental discoveries and applications. No matter how sophisticated the microscopic or phenomenological approach adopted to deal with this topic, one of the central problems to the complete understanding of nonlinear processes is always the solution of the associated wave propagation equation, which is, of course, intrinsically nonlinear. This circumstance can be considered in many cases as an obstacle to a full comprehension of the problem, due to the well-known mathematical difficulties usually encountered when trying to solve this type of equation. However, it is precisely the nonlinear nature of the wave equation which gives rise to a wealth of solutions, and thus of possible behaviors of the propagating field, and makes nonlinear optics much more interesting than its linear counterpart.
© 1998 Società Italiana di Fisica. (Ricevuto il 12 Gennaio 1998). The authors would like to dedicate this review to their graduate students and post-doctoral fellows whose ingenuity and enthusiasm has significantly contributed to the effort of understanding and observing photorefractive solitons: MING-FENG SHIH, M. MITCHELL, ZHIGANG CHEN, E. DELRE, G. DUREE, K. KOS, M. MORIN, C. ANASTASIOU, SONG LAN, H. MENG, S. HAWKINS and M. CHAUVET