טכניון מכון טכנולוגי לישראל
הטכניון מכון טכנולוגי לישראל - בית הספר ללימודי מוסמכים  
M.Sc Thesis
M.Sc StudentUzdin Raam
SubjectAspects of Solitons
DepartmentDepartment of Physics
Supervisor ? 18? Mordechai Segev


Abstract

This thesis deals with several aspects of spatial solitons.


Chapter 1 - Theory of the resonance nonlinearity and resonance solitons. The theory explains the surprising observation of very narrow self trapped optical beams in iron doped photorefractive Indium Phosphide crystals. Two new predictions are provided, one of which has been successfully demonstrated .


Chapter 2 - Radiation Reaction: The force an electron exerts on itself when accelerated. Here this force is derived by a very simple caclculation. The relation to  Dirac's work and the Wheeler-Feynman model is discussed. The simplicity and comfort of this method is demonstrated for the case of an oscillating wire .


Chapter 3 is about the first observation of propeller solitons by our group. Propeller soliton are ''solitons'' whose intensity structure rotates as it propagates. After a short discussion a new intuitive description of the rotation mechanism is given. Finally two minor, yet interesting effects are predicted .


Chapter 4 shows how an electrical charge can be assigned to photorefractive solitons. Two charged solitons can undergo novel long range ''electrostatic'' inteaction, and a single charged soliton can be steered by an external electric field. An experimental evidence for this steering effect is presented


Chapter 5 - An exciting analogy between spatially incoherent light in nonlinear medium and Thermal physics is presented .


Chapter 6 explores the phase of spatially incoherent light patterns emerging in nonlinear medium. We define a new global measure of  a pattern’s spatial phase fluctuations. A relation between this measure and the intensity of a pattern is derived. Usind this measure we find that eventually the system reaches an equilibrium. 


Chapter 7 presents a new description of solitons and guided modes based on complex space (coordinates). In this picture the propagation of a beam is described by a trajectory (like particles) in the complex space.