Active mirror alignment for free electron lasers

• Main Author: Fiorani, Fulvia M.
• Other Authors: Denardo, Bruce C.
• Published: Monterey, Calif. Naval Postgraduate School 2012
• Online Access: http://hdl.handle.net/10945/3981

This thesis investigates active mirror alignment systems of a free electron laser (FEL) for future integration as a ship self-defense weapon. An issue with this integration is the effect of low-frequency shipboard vibrations on the optical cavity mirrors. Alignment of the cavity mirrors is required for the proper operation of any type of laser. Mirror alignment is especially critical for an FEL because the electron beam and optical mode must substantially overlap. Laboratory FEL facilities, along with other laboratory high energy facilities that employ active mirror alignment systems, are investigated. In addition, a model theory for controlling the vibrations of a single-degree-of-freedom system is developed, and experiments with a simple mirror alignment system are described. Reduction of an impressed vibration amplitude by a factor of five is achieved, compared to a factor of fifteen that is achieved in major laboratory systems with sophisticated control systems. The purpose of these efforts is to understand the underlying physics of vibration control. The knowledge forms a basis for follow-on research towards the development of a prototype shipboard active mirror alignment system.