E- source R&D update ILC source laser project Faraday rotation experiment A. Brachmann 05/07/07 SLAC R&D meeting

Mode-locked pulse train (76 MHz) 05/07/07 SLAC R&D meeting

MIRA Power Mode of operation Power SLAC R&D meeting cw alignment cavity 0.93 W Main cavity 0.8 W Mode-locked operation 0.45 W (76 MHz, 5.9 nJ) 05/07/07 SLAC R&D meeting

MIRA wavelength tuning curve ~ 760 nm To get peak at 780 nm we need new cavity optics 05/07/07 SLAC R&D meeting

MIRA efficiency 05/07/07 SLAC R&D meeting

MIRA ML spectrum SLAC R&D meeting FWHM = 2.8 nm = 760 nm BW [Hz] = (FWHM*3*108) / 2 T = 0.44 / BW = 300 fs Stretching by a factor of ~ 3000 to obtain 1 ns 05/07/07 SLAC R&D meeting

Extend cavity to reduce repetition rate and increase peak power Near term plans Extend cavity to reduce repetition rate and increase peak power Measure pulse width (Auto-correlator) Pulse stretching 3 MHz train generation using fast Pockel’s cell 05/07/07 SLAC R&D meeting

Faraday Rotation Experiment Measures Depolarization Dynamics Depolarization occurs during transport through cathode material Understanding depolarization allows design of optimized photocathodes 05/07/07 SLAC R&D meeting

Faraday Rotation Experiment Schematic 05/07/07 SLAC R&D meeting

Depolarization Dynamics Measurement General shape, Not a measurement! 05/07/07 SLAC R&D meeting

Faraday Rotation Experiment Status Ar – Ion laser 20 + years old Converted from multi line to single line operation Evaluating and improving stability of Ar – ion laser Experiment set up complete Detector setup optimization options: Low noise photodiodes CCD camera (loan of ICCD from SPPS) 05/07/07 SLAC R&D meeting