14/7/16

You are invited to attend a lecture

Optimisation of Radiation Power Extraction and Control of Laser Spectrum in an Electrostatic Free Electron Laser Oscillator

By

Harry Marks

PhD student of

Professor Avraham Gover

Physical Electronics Department, Tel Aviv University

This talk will began by introducing the subject of free electron lasers with a special emphasis on electrostatic accelerator free electron laser oscillators. The operating principles and major components of such a device will be discussed.

Results of an experimental study of the saturation dynamics and the optimal conditions for maximal radiation power extraction in a free electron laser (FEL) oscillator will be presented. The study was conducted on the Israeli electrostatic accelerator free electron laser (EA-FEL) that is capable of providing lasing pulses at frequencies between 95–110 GHz (depending on the electron beam energy). One critical parameter affecting the performance of the laser is the reflectivity and transmission of the out-coupling element of the resonator. Varying this parameter was made possible by attaching a remote-controlled variable reflectivity out-coupling element (based on a series of wire-grid polarizers) to the resonator of our EA-FEL.

Another critical way to change lasing power is through post-saturation variation of the energy of the electron beam during the lasing period. It will be shown that post-saturation, positively ramping the beam energy increases the radiation extraction efficiency by around 50%. Whilst a falling beam energy results in a reduction in extraction efficiency.

Thursday, July 14, 2016, at 15:00

Room 011, Kitot Building