Transcript Laser Overview_PRB.ppt

Drive Laser Introduction
• ‘ir’ master oscillator power amplifier chain
(MOPA) uses standard chirped pulse
amplification scheme (CPA)
• third harmonic generation (THG) produces
required uv for photocathode irradiation
• ‘ir’ master oscillator is a mode-locked source
which is locked to external RF
• Finesse and Reliability are key – stabilities and
shaping
• readily accommodate technical upgrades
LCLS Drive Laser
Sections
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Oscillator
Temporal Pulse Shaping
Preamplifier
Final Amplifier
UV Conversion and Pulse Shaping
UV Transport (to photocathode)
Other Beamlines
(EO diagnostic, laser heater,…)
Drive Laser Architecture:
TiS mode-locked oscillator
@ 119 MHz (ext reference)
& with few nm bandwidth
Spatial
filtering
& pulse
compression
Relay
Imaging
Temporal
Pulse
Shaper
Temporal
Stretcher
Power amplifier
with pumps
UV Conversion and wavelength
separation
KHz pulse
selection
120 Hz
Pulse
selection
UV Profile Shaping and
Transport
to Photocathode
Preamplifier
with pump
Injector
Photocathode
oscillator +
pump (few nJ)
shaper +
stretcher
KHz pulse
selection
isolator
(estimate
combined
efficiency 10-15 %)
crosscorrelator
diagnostic
compressor
Probe 1 &
oscillator
diagnostics
Probe 2 &
diagnostics
4x30Hz
Splitter
isolator
preamplifier
+ pump
(few mJ)
Probe 3 &
preamplifier
diagnostics
to TiS final
amplifier
(eg. four arms)
Final Amplifier - Plan A:
From 4x30
Hz splitter
30 Hz pump
(500 gr mJ)
Energy
stabilization
TiS
80-100 mJ
(3 W @ 30
Hz)
combiner
30 Hz pump
(500 gr mJ)
Energy
stabilization
TiS
30 Hz pump
(500 gr mJ)
Energy
stabilization
TiS
30 Hz pump
(500 gr mJ)
Energy
stabilization
80-100 mJ
(6 W @ 60
Hz)
uv
80-100 mJ generation
High power
(12 W @
compressor
120 Hz)
combiner
combiner
uv profile
flattener
TiS
Multipass
amplifier heads
(eg. four pass)
uv to
photocathode
blue to EO
ir to laser heater
Beamlines
crystal
pair
wavelength
separation
unconverted
ir to laser
heater
uv profile
flattener
unconverted
blue to EO
diagnostic
uv to photocathode
( mJ)
Some Drive Laser Challenges
- final amplifier designs : plans A and B
(minimize ‘ir’ pulse energy requirements)
- STABILITIES such as ‘uv’ pulse energy
stability (done at ‘ir’ level)
- optimize uv conversion efficiency
(‘ir’ temporal shaping effects, pulse quality for
unconverted light)
- ‘ir’ control of uv temporal pulse shape
- uv profile shaping and efficient uv transport (final
launch phase…)
- essential prototyping (FY’04 especially)
- readily accommodate repairs and technical
upgrades during LCLS operation