3D Laser pulse shaping for photoinjector applications Yuelin Li Accelerator Systems Division and X-ray Science Division Argonne National Laboratory [email protected]

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


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


Outline











– Results Summary and acknowledgement


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.)

{


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


Outline











– Results Summary


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).


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).


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

=


Phase tailoring

t

Chromatic dispersion for ellipsoidal pulse

Chromatic dispersion

+

Radius modulation


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(),(),(


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)


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%,


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


Outline











– Results Summary


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).


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).


Data processing example

Raw Ip

Fringe map im


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


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).


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


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


Outline











– Results Summary


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

Documents

3D Laser pulse shaping for photoinjector applications Yuelin Li Accelerator Systems Division and X-ray Science Division Argonne National Laboratory [email protected]