1. CTF3 Laser Status Massimo Petrarca CLIC January 23 2008

2. 3-pass Nd:YLF amplifier x300 3 pass Nd:YLF amplifier x5 Probe Beam General LASER LayOUT: Optical gate (Pockels cell) 22 44 UV pulses 1.24  s Drive Beam Brewster plate 1.5 GHz Nd:YLF Oscillator 1.5 GHz Nd:YLF preamplifier Phase Coding Micro pulses at 1.5 GHz ~666ps 400us amplification window for AMP1 Macro pulse 200us amplification window for AMP2 Macro pulse

3. General pulse structure layout not in scale Oscillator & Preamplifier 1.5 GHz; 10W AVG Power AMP1 @ 90A 400 us; 5Hz 3KW Peak Power AMP1 + AMP2 @90 A 400 us;200us 5Hz 14 KW Peak Power 400us amplification window for AMP1 Macro pulse 200us amplification window for AMP2 Macro pulse Micro pulses at 1.5 GHz ~666ps

4. Step by Step characterization Time structure (3 passes configuration) of the macro pulse coming out of AMP1 Power, Energy Measured @ 90A Zoom in The peak power of the macro pulse thus the the gain and micro pulse energy are well above the specs 1.5 GHz Nd:YLF Oscillator+ preamplifier 3-pass Nd:YLF amplifier 400  s, 5 Hz diode pump 15 kW Project specification: ~3 kW ; 2  J/pulse 3 pass Nd:YLF amplifier diode pump 5 Hz

5. Step by Step characterization Time structure (2 passes configuration): Gain, Peak Power and Energy when AMP1 and AMP2 are both 90A 1.5 GHz Nd:YLF Oscillator+ preamplifier 3-pass Nd:YLF amplifier 400  s, 5 Hz diode pump 3 pass Nd:YLF amplifier 5 Hz diode pump Project specification: ~15 kW ; 10  J/pulse Which is the expected value for the amplifier output power when diode arrays are driven by 90amps current (18 KW pumping power) each? 3-lens system with 1.2 magnification yields a good matching between the transverse beam size of the beam and the rod.

6. 1.5 GHz Nd:YLF Oscillator 1.5 GHz Nd:YLF preamplifier Phase Coding 3-pass Nd:YLF amplifier x300 AMP1 behavior vs oscillator input power In order to obtain an AMP1 satisfactory power response an oscillator power of at least 36 mW is needed.

7. AMP1 oscillation behavior vs oscillator input power In order to obtain an AMP1 satisfactory power response an oscillator power of at least 36 mW is needed, but oscillation in the beam intensity increases the oscillator output power limit from 36mW to 82 mW

8. Conclusion : The power of the first amplifier is satisfactory as well as the time structure (saturation region). Its transverse beam profile has to be optimize The power of the first amplifier is satisfactory as well as the time structure (saturation region). Its transverse beam profile has to be optimize Regarding the second amplifier: Regarding the second amplifier: the power is still not satisfactory for the specification of the project. Which should be the value for the pumping power in order to obtain the 15 KW of the amplified beam? (Talk to RAL). The transverse beam profile is satisfactory comparing it with the beam profile of the input (into AMP2). the power is still not satisfactory for the specification of the project. Which should be the value for the pumping power in order to obtain the 15 KW of the amplified beam? (Talk to RAL). The transverse beam profile is satisfactory comparing it with the beam profile of the input (into AMP2). Investigation of the oscillation in the amplified beam for 36mW of input power into the preamplifier must be done: are the oscillation causes by instability of the preamplifier or by AMP1? Investigation of the oscillation in the amplified beam for 36mW of input power into the preamplifier must be done: are the oscillation causes by instability of the preamplifier or by AMP1? Pockels cell is installed and works properly. Pockels cell is installed and works properly. Installation of the quadrupling crystals will be done in few days. Installation of the quadrupling crystals will be done in few days.

9. The End