1. Califes Laser Optical design
M Gilbert – P.Y Thro - G.Cheymol Laboratoire Interaction Laser Matière/SCP/DPC/DEN/DANS/CEA Saclay
DEPARTEMENT DE PHYSICO-CHIMIE
DEN/Saclay
CTF3 coll meeting jan 07

2. Laser-Matter Interaction Lab. : competences
Complex optical systems and processes using the laser-matter interaction
optimisation
PROCESSES
valorisation
Laser physics
Optics
Laser ablation
Active pyrometry
Laser produced plasma
Surface treatment
OPTICAL SYSTEMS
Laser-matter
interaction
Diode-pumped solid-state lasers
Frequency conversion
In-situ analysis in hostile environment
Optical fiber technologies
Innovative instrumentation
MODELLING
interpretation
prediction
Laser-matter Interaction
Modelling of solid-state laser
Simulation of optical systems
Physicochemistry of surfaces
DEPARTEMENT DE PHYSICO-CHIMIE
DEN/Saclay
CTF3 coll meeting jan 07

3. µpulse:1.5GHz,6ps, 10mJ/pulse
Global Scheme
Drive Beam
Probe Beam
drive beam
output
Oscillator + préamp
1047 nm
1.5GHz; 10ps
10W; 6.7 nJ/pulse
Ampli n°1 et n°2
macropulse:5 Hz,270µs
20W;
µpulse:1.5GHz,6ps, 10mJ/pulse
Pulse shaping
&
stabilisation
Drive Beam
gun t
Spare beam :
 for probe beam t
To simplify the following
views t
Pulse selector
& mixer
1.5 GHz  3GHz
1 to 64 3GHz
GHz
Frequency Conversion
ω  4ω
1047nm to 262 nm
η=12%
Beam transport ~ 80m
&
Position control
Probe Beam
gun
DEPARTEMENT DE PHYSICO-CHIMIE
DEN/Saclay
CTF3 coll meeting jan 07

4. Pulse selector and mixer: 1.5 GHz 3 GHz
25ns
Optical delay
7.5 m (25ns)
Combination through
a polariser t
1to64 3 GHz t
zoom
1to GHz
max 21.3 ns t
Scheme of 2 pulses to be selected and combined
to generate à 3 GHz beam.
~20µs
DEPARTEMENT DE PHYSICO-CHIMIE
DEN/Saclay
CTF3 coll meeting jan 07

5. Pulse picker: details and combination
DEPARTEMENT DE PHYSICO-CHIMIE
DEN/Saclay
CTF3 coll meeting jan 07

6. Pulse picker: specifications
Transmission expected
time diagram
Mains specifications for the pulse picker:
sharp rise and fall time: ~400 ps (period:1.5 Ghz 666ps)
duration ~ 0.5 ns to 85 ns with stability better than ± 1.25%
- low transmission (< 4%) out of the pulse selected
- need of high transmission on tranmitted beam but also on rejected beam (T to be confirmed)
DEPARTEMENT DE PHYSICO-CHIMIE
DEN/Saclay
CTF3 coll meeting jan 07

7. Frequency conversion – Type of crystal2w
TYPE I : e
Optical axis w o 2w e w
TYPE II : o
Optical axis
DRIVE BEAM :
ω  2ω BBO type I ;
2ω  4ω BBO type I
PROBE BEAM :
ω  2ω KTP, LBO type II  ;
2ω  4ω BBO, CLBO type I
DEPARTEMENT DE PHYSICO-CHIMIE
DEN/Saclay
CTF3 coll meeting jan 07

8. Frequency conversion – parameters
KTP (II)
LBO (II)
BBO (I)
CLBO (I)
ω -> 2 ω
2ω -> 4 ω
 incident (nm)
1047
523
deff :non linearity coeff (pm.V)
3.0
0.62
1.74
0.8
L : length of crystal (cm)
0.6
1.5
1/e²: diameter (mm)
1.8
1.14
2.04
2.1
Tolerance:
Angular acceptance: =   2  /acc  
0.028
0.125
0.48
0.32
Walk-off :  =2.max..L / 
0.038
0.17
0.67
0.44
GVM : GVM = GVM.L /Dt1/2
0.267
0.97
1.04
Typical parameters and tolerances
calculations for entering beam parameters: 10µJ, 6ps, 1047 nm, M²(beam quality factor) =1
and for CE (conversion efficiency) =35% ( 12% for  -> 4)
DEPARTEMENT DE PHYSICO-CHIMIE
DEN/Saclay
CTF3 coll meeting jan 07

9. Optical path on « laser table » / provisional
DEPARTEMENT DE PHYSICO-CHIMIE
DEN/Saclay
CTF3 coll meeting jan 07

10. Optical relay /afocal system
disturbance A A’ ft d
Optical relay reduce consequences of miroir vibration, air turbulence in plane A’
3 lenses afocal system allows to:
- decrease the footprint of the optical system for a given relay distance.
- change Gy and relay distance (to some extent)
DEPARTEMENT DE PHYSICO-CHIMIE
DEN/Saclay
CTF3 coll meeting jan 07

11. « under the roof » long distance beam delivery
2 afocal optical relay:
L1-L2 with f~ 10 m
L3-L4 with f~ 7.5m
DEPARTEMENT DE PHYSICO-CHIMIE
DEN/Saclay
CTF3 coll meeting jan 07

12. under air / under vacuum beam delivery
Concequence of Temperture and Pressure variations:
n-1 (~ ) proportional to P et T. n: air optical index
l = 80m and ΔT or ΔP = 1%  Δ (n .l) ~ 0.3mm  Δt ~ 1 ps.
Attenuation 262 nm):
Rayleigh Diffusion  Transmission = 98%.
Ozone absorption:
= ~10-17 cm-2 (max at 255 nm) : absorption cross section
40 ppb ozone, l= 80m  T=92%.
 Transport under vacuum to be prefered
DEPARTEMENT DE PHYSICO-CHIMIE
DEN/Saclay
CTF3 coll meeting jan 07

13. « photoinjector » optical table
DEPARTEMENT DE PHYSICO-CHIMIE
DEN/Saclay
CTF3 coll meeting jan 07