3D Laser pulse shaping for photoinjector applications
Yuelin Li
Accelerator Systems Division and X-ray Science Division
Argonne National [email protected]
2ERL 2009, Ithaca, June 9, 2009
Acknowledgement
K. Harkay, K.-J. Kim, and E. Gluskin for strong support J. Lewellen, Y. Sun for discussion and help with GPT
simulation S. Chemrisov for helping with experiments This work is support by DOE, Office of Basic Science
3ERL 2009, Ithaca, June 9, 2009
Outline
The case of pulse shaping: high brightness or low emittance
– Thermal/cathode emittance: casted after emission
– Emittance growth due to space charge force: can be compensated
– Uniform ellipsoidal beam is the key Pulse shaping techniques
– Mechanical: pulse stacking
– Physics: self evolving
– Phase modulation: • Mechanism• optics and beam simulation
Progress at ANL: A proof of principle experiment
– Measurement method
– Phase tailoring procedure
– Results Summary
4ERL 2009, Ithaca, June 9, 2009
Outline
The case of pulse shaping: high brightness or low emittance
– Thermal/cathode emittance: casted after emission
– Emittance growth due to space charge force: can be compensated
– Uniform ellipsoidal beam is the key Pulse shaping techniques
– Mechanical: pulse stacking
– Physics: self evolving
– Phase modulation: • Mechanism• optics and beam simulation
Progress at ANL: A proof of principle experiment
– Measurement method
– Phase tailoring procedure
– Results Summary and acknowledgement
5ERL 2009, Ithaca, June 9, 2009
The case of pulse shaping
The case of pulse shaping:
– Theory of emittance compensation• Emittance growth due to space charge force can be
compensated if the space charge force is linear– Carlsten, NIMA 285, 313, (1989)– Serafini and Rosenzweig, PRE 55, 7565 (1997)
– Homogeneous ellipsoidal beam is the key• Uniform electron density distribution in a ellipsoid• Has linear space charge force (M. Reiser, Theory and Design of
Charged Particle Beams, Wiley, New York.)
{
6ERL 2009, Ithaca, June 9, 2009
Space charge force distribution: three geometries
-4 -3 -2 -1 0 1 2 3 4-1.0
-0.5
0.0
0.5
1.0
E
z (au
)
z (mm)
Ez
-1.5 -1.0 -0.5 0.0 0.5 1.0 1.5-1.0
-0.5
0.0
0.5
1.0
Ez (
au)
z (mm)
Ez
-1.5 -1.0 -0.5 0.0 0.5 1.0 1.5-1.0
-0.5
0.0
0.5
1.0
Ez (a
u)
z (mm)
Ez
3D Gaussian Cylindrical
H. Ellipsodial
7ERL 2009, Ithaca, June 9, 2009
Outline
The case of pulse shaping: high brightness or low emittance
– Thermal/cathode emittance: casted after emission
– Emittance growth due to space charge force: can be compensated
– Uniform ellipsoidal beam is the key Pulse shaping techniques
– Mechanical: pulse stacking
– Physics: self evolving
– Phase modulation: • Mechanism• optics and beam simulation
Progress at ANL: A proof of principle experiment
– Measurement method
– Phase tailoring procedure
– Results Summary
8ERL 2009, Ithaca, June 9, 2009
Pulse stacking
Excellent for longitudinally flat topped pulse
– Interferometer setup• C. Sider, Appl. Opt. 37, 5302 (1998).
– Bi-fringence crystals• C. S. Zhou, et al., Applied Optics 46, 1 - 5 (2007).• I.V. Bazarov, D.G. Ouzounov, B.M. Dunham, Phys. Rev. ST AB 11, 040702 (2008).
For uniform ellipsoidal pulse generation: very complicated
– First beam simulation by Limborg• C. Limborg-Deprey and P. Bolton, Nucl. Instrum. Methods A 557, 106
(2006).
– Design exists, but with low efficiency • H. Tomizawa, private communication).
9ERL 2009, Ithaca, June 9, 2009
Self-evolution of the a pancake beam
Pro
– Easy: Need a short pulse (100 fs) with initial parabolic transverse distribution, no longi shaping needed
Con
– Cannot put too many charges: image charge will distort the beam
– Pancake geometry thus larger transverse size: larger cathode emittance to start with
L. Serafini, AIP Conf. Proc. 413, 321 (1997).O. J. Luiten et al, Phys. Rev. Lett. 93, 094802 (2004).B. J. Claessens, Phys. Rev. Lett. 95, 164801 (2005).J. B. Rosenzweig et al., Nucl. Instrum. Methods A 557, 87 (2006). P. Musumeci, et al., Phys. Rev. Lett. 100, 244801 (2008).
10ERL 2009, Ithaca, June 9, 2009
Pulse shaping: 3D laser pulse shaping to generate an ellipsoidal beam
Difficulties
– Simultaneous evolving longitudinal and transverse profiles
– Homogeneous in 3-D
– Actually a 2-D problem due to rotation symmetry Hope: coupling between time and space via chromatic dispersion
Phase: ()Amplitude: A()
Frequency domain
Phase: (t)Amplitude: A(t)
Size: r(t)Amplitude: A(t)
Chromaticdispersion
Time domain
Spatiotemporal
=
11ERL 2009, Ithaca, June 9, 2009
Phase tailoring
t
Chromatic dispersion for ellipsoidal pulse
Chromatic dispersion
+
Radius modulation
12ERL 2009, Ithaca, June 9, 2009
Can an ellipsoidal pulse be generated?
d
dn
n
ff
RRn
f 1
111)(
)(
1
0
0
21
Y. Li and J. Lewellen, PRL 100, 078401(2008)
fw
z
fww Rzf
R
2/12
0
)(1)(
A EM pulse can be written as
An ellipsoidal pulse
Chromatic Dispersion
Gaussian beam
Therefore
consttrA
Ttrtrb
),(
/1)( 2max
2/120
1
2/12
00
22
/1)(
sin12
)()()(
/1~)(/1~)(
TtAtA
T
tT
T
tttdttdttt
TttwTtt
dttt
titrAtrE
)()(
))(exp(),(),(
13ERL 2009, Ithaca, June 9, 2009
Numerical calculation: Fourier optics method
Full wave optics (Fresnel diffraction) adapted from Kempe et al. (JOSA B 9, 1158 (1992))
Group velocity dispersion and group velocity delay effect considered up to the second order
Kempe et al.,JOSA B 9, 1158 (1992)
14ERL 2009, Ithaca, June 9, 2009
The 3D laser pulse at the focal plane of a lens
f=150 mm, 249 nm, 12 ps FW Li, Lewellen and Chemerisov, PRSTAB 12, 020702 (2009).
0 5 10 150.0
0.2
0.4
0.6
r (m
m)
0 5 10 15
rx2
0 5 10 15
rx4
t (ps)
0 5 10 15
rx8
0 5 10 15
rx16
=8%, 4%, 2%, 1%, and 0.5%, a0=25 mm,
0 5 10 150.0
0.2
0.4
0.6
r (m
m)
0 5 10 15
rx2
0 5 10 15
rx4
t (ps)
0 5 10 15
rx6
0 5 10 15
rx12
a0=25, 12, 6, 4, and 2 mm, =8%,
15ERL 2009, Ithaca, June 9, 2009
Performance at 1 nC very promising in simulation
0 2 4 6 8 10
0.4
0.8
1.2
Beer can Egg Pancake Shaped
(c)
x (m
m m
rad)
z (m)
Y. Li and J. Lewellen, PRL 100, 078401(2008)
Simulation condition for LCLS from: M. Ferrario et. al., Proc. EPAC 2000, p. 1642.
-4 0 4 80.0
0.2
0.4
0.6
r (m
m)
(a)
t (ps)
0
0.5
1.0
Spatiotemporal profile Emittance
16ERL 2009, Ithaca, June 9, 2009
Outline
The case of pulse shaping: high brightness or low emittance
– Thermal/cathode emittance: casted after emission
– Emittance growth due to space charge force: can be compensated
– Uniform ellipsoidal beam is the key Pulse shaping techniques
– Mechanical: pulse stacking
– Physics: self evolving
– Phase modulation: • Mechanism• optics and beam simulation
Progress at ANL: A proof of principle experiment
– Measurement method
– Phase tailoring procedure
– Results Summary
17ERL 2009, Ithaca, June 9, 2009
A proof of principle experiment
Experimental setup
– 800 nm laser, 1 kHz, 10 nJ per pulse, 40 nm bandwidth
– ZnSe lens as the focal lens for high dispersion • 25-mm diameter, 88.9-mm radius of curvature, and 2.9-mm center thickness, Janos
Technology, A1204-105, • Dispersion 250 fs2/mm at 800 nm )
– DAZZLER as the phase modulator
– Achromatic lens for transport
C
ALZSL
SF
PP
D
ODL
PP: pulse picker; D: AOPDF; SF: achromatic spatial filter; ZSL: ZnSe lens; AL: achromatic image relay lens; ODL: optical delay line; C: camera.
Y. Li and S. Chemerisov, Opt. Lett. 33, 1996 (2008); Li, Lewellen and Chemerisov, PRSTAB 12, 020702 (2009).
18ERL 2009, Ithaca, June 9, 2009
The signal recorded on the camera is
If probe is much shorter than the main pulse
Measuring the contrast ratio C(,r), and integrated probe intensity Ip(r),
3D mapping method
.))(()(cos),)((),()]([cos2
)()(),(
dttttAtA
III
pmpm
pm
rrrrr
rrr
.)(),()]([cos2)()(),( rrrrrr pmppm IitIII Interference term
Main beam profile at
.)(
),(),(
2
r
rr
pm I
Ci
Y. Li and S. Chemerisov, Opt. Lett. 33, 1996 (2008).Li, Lewellen and Chemerisov, PRSTAB 12, 020702 (2009).
19ERL 2009, Ithaca, June 9, 2009
Data processing example
Raw Ip
Fringe map im
20ERL 2009, Ithaca, June 9, 2009
Phase and amplitude modulation viaAcousto-optic Programmable Dispersive Filter (DAZZLER)
A device widely used in laser and optical research– F. Verluise, V. Laude, Z. Cheng, Ch. Spielmann, and P. Tournois, Opt. Lett. 25, 575
(2000).
DAZZLER and similar phase modulation device have been applied to photoinjector related laser pulse shaping for cylindrical pulse– H. Tomizawa et. al., Nucl. Instrum. Methods A 557, 117 (2006).
– J. Yang, et al., J. Appl. Phys. 92, 1608 (2002).
– S. Cialdi, et al., Appl. Opt. 46, 4959 (2007). UV version available
UV version available– http://fastlite2.siteo.com/en/page15.xml
– T. Oksenhendler, CLEO 07
266 nm
21ERL 2009, Ithaca, June 9, 2009
Generating the desired phase and amplitude modulation
760 800 8400.0
0.5
1.0
-3036101316
-1.0 -0.5 0.0 0.5 1.00.0
0.5
1.0
-4-2024
(b)A (ar
b. u
nits)
(nm)
()
(a)
t (ps)
Calculate the time domain amplitude and phase
Fourier transform for frequency domain for desire spectrum
Take a spectrum of the laser and calculate the spectrum to load to the DAZZLER
Load the spectrum and phase to the DAZZLER
Y. Li and S. Chemerisov, Opt. Lett. 33, 1996 (2008).
22ERL 2009, Ithaca, June 9, 2009
Results for a Gaussian beam with different aperture size
Excellent between data and simulation Work for the future
– Demonstration in UV with larger beam– Beam experiment
-1 0 1 -1 0 1-1 0 1-1 0 1
0.0
0.5
1.0
t (ps)
I (ar
b.u
nits)
P = 12 mm
-30
0
30
r (m
)
P = 2 mm
-30
0
30
P = 3 mm
P = 4 mm
-6 -4 -2 0 2 4 6
-6
-4
-2
0
2
4
6
x (mm)
y (m
m)
Input beam
Y. Li and S. Chemerisov, Opt. Lett. 33, 1996 (2008).Li, Lewellen and Chemerisov, PRSTAB 12, 020702 (2009).
Data
Sim
Comp
23ERL 2009, Ithaca, June 9, 2009
Effect of residual linear chirp
Beam radius: 1/e2 width of 3 mm
-1 0 10.0
0.5
1.0
-1 0 1 -1 0 1 -1 0 1-1 0 1
-20
0
20 a=-4125 fs2
r (
m)
i (ar
b. u
.)
-20
0
20
a=-2625 fs2
a=1875 fs2
a=-4875 fs2
a=0 fs2
time (ps)
Li, Lewellen and Chemerisov, PRSTAB 12, 020702 (2009).
Data
Sim
Comp
24ERL 2009, Ithaca, June 9, 2009
Outline
The case of pulse shaping: high brightness or low emittance
– Thermal/cathode emittance: casted after emission
– Emittance growth due to space charge force: can be compensated
– Uniform ellipsoidal beam is the key Pulse shaping techniques
– Mechanical: pulse stacking
– Physics: self evolving
– Phase modulation: • Mechanism• optics and beam simulation
Progress at ANL: A proof of principle experiment
– Measurement method
– Phase tailoring procedure
– Results Summary
25ERL 2009, Ithaca, June 9, 2009
Summary
Current status
– Laser pulse shaping may generate 3D shaped pulses, potentially uniform ellipsoid
– A 3D mapping method is developed Issues
– High rep rate and longer pulse duration: longer crystals• Fastlite, private communications
Future plan
– Generating a flat topped beam as input
– Demonstration in UV
– Beam generation