טכניון מכון טכנולוגי לישראל
הטכניון מכון טכנולוגי לישראל - בית הספר ללימודי מוסמכים  
M.Sc Thesis
M.Sc StudentMizrahi Amit
SubjectDesign and Analysis of Optical Bragg Acceleration Structures
DepartmentDepartment of Electrical Engineering
Supervisor Professor Levi Schachter


Abstract

Particle accelerators are devices that convert energy from an electromagnetic field into kinetic energy of charged particles. Currently, high energy accelerators are made of metallic waveguides that operate at microwave frequencies and are a few kilometers long. The availability of high power lasers and the ability to fabricate dielectric micron scale structures make the idea of dielectric optical accelerators appealing. At optical wavelengths, the acceleration structures will be considerably smaller and less expensive. Feasibility proof of this possibility will ultimately lead to a major progress in accelerator technology, and may even pave the way to table-top laser accelerators. It is demonstrated that a Bragg reflection waveguide consisting of a series of dielectric layers may form such an optical acceleration structure. A design procedure for a device that exhibits confinement of the accelerating fields is given for both planar and cylindrical (hollow optical fiber) structures. Analysis of acceleration parameters such as the interaction impedance and the energy velocity shows that a typical structure made of Silica and Zirconia is adequate for acceleration purposes. An evaluation of the wake-field created by the motion of a train of electron micro-bunches along the structure is also provided. A qualitative analysis is given in case of a relatively small number of layers, and quantitative results are given for a higher number of dielectric layers, showing that in comparison to a structure bounded by metallic walls, the effect on trailing bunches is significantly smaller due to propagation bands allowing electromagnetic energy to escape.