Cheiron School 2008

Pump/Probe Experiments

T. Gejo(University of Hyogo)

Today’s Topics• Univ. of Hyogo? Where is it?
• General aspects of pump/probe experiments• Laser/Synchrotron pump/probe experiments• FEL/Laser pump probe experiments• Storage-Ring-FEL/SR pump probe experiments1

Today’s Topics• Univ. of Hyogo? Where is it?
• General aspects of pump/probe experiments• Laser/Synchrotron pump/probe experiments• FEL/Laser pump/probe experiments• Storage-Ring-FEL/SR pump/probe experiments2What is pump/probe experiment?
Laser（probe）

exited state

Pulse laser(Nano second,or femto second Laser)

Laser（pump）

ground state
ΔT
Time dependent measurements
Spectroscopy
Quantum Information

Basic scheme of pump/probe experiments
Fluorescence
Ions
Electrons
probe

pump

ΔT

Wavelength

ΔT

3Other spectroscopic techniques of pump/probe experiments
Ions
Electrons
Fluorescencepump

Threshold

probe

probe

ΔT

pump

ΔT
Wavelength of probe
Depletion techniqueStimulated Emission Pumping technique

Wavelength of pump

Example pf pump/probe experiment4

One of the examples (Angular distributions of photoelectrons)"Non-adiabatic dynamics effects in Chemistry revealed by time-resolved charged particle imaging"Toshinori Suzuki and Benjamin J. Whitaker, Int. Rev. Phys. Chem.20, 303 (2001).

Today’s Topics• Univ. of Hyogo? Where is it?
• General aspects of pump/probe experiments• Laser/Synchrotron pump/probe experiments• FEL/Laser pump/probe experiments• Storage-Ring-FEL/SR pump/probe experiments

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Laser/Synchrotron pump/probe experiments
Laser（probe）
SR（pump）

exited stateexited stateSR（pump）

Laser（probe）

ground state
ΔTground state
ΔTTime dependentmeasurements :photoelectron spectra,
X-ray diffraction

Spectroscopy ofhighly excitedstate

One big difficulty of pump/probe experiments with Laser/SRSRSR

Laser

Ionization potentialexited state
Laser
Signals due to SR only
gives high Back ground noiseLaserground state

When you measure ofphotoelectron spectra….
Other problems
X-ray penetrates deeper.
Repetition frequency of the pump-probe experimentis limited by sample.

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Examples 1
Laser/SR(IR)@UVSORIR and Laser spectroscopy at UVSOR

Excited state

Relaxation

IR absorption

Two photon excitation
Ground state

PbBr2,PbCl2

J. Azuma, M. Kamada, M. Itoh et al. (UVSOR)

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Experimental set up

Ti:sapphirehn=3.0eV
1 kHz150 fs

Storage Ring

BL-6A2

BL-6A1

Laser

BrukersampleResults
1.0

DO.D.

PbBr 2 T=13K
0.5

Laser ON－) Laser OFF
0.0
1.0

DO.D.

• PbBr2、PbCl2

DO.D.

PbCl 2 T=13K

0.5

0.0 0

2000

4000

6000

8000-1

Wavenumber (cm )10000

J. Azuma, M. Kamada,
M. Itoh et al.

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Examples 2
Laser/SR(VUV)@UVSOR

T. Tsujibayashi, et al. PRL 94 076401 (2005)

9BaF2T. Tsujibayashi, et al. PRL 94 076401 (2005)

AF luminescence detected by dual MCA system

Laser Timing

0-15-10-502001015(a)Laser (3.1 eV)+SR (18.4 eV)

laserONCounts

5Accumulated
for 2700 sec.
0-15200-10-50510• Time evolution of AF
luminescence withlaser (laser ON) andwithout laser (laserOFF).

15(b)SR (18.4 eV)
Accumulated
for 2700 sec.

LaserOFF
0-15-10-50Time (ns)5101510BaF2T. Tsujibayashi, et al. PRL 94 076401 (2005)

Examples 3
Laser/SR(X-ray)@Spring-8

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Time-resolved X-ray Scattering
Observe the changeof diffraction pattern!!
X-ray (probe)

pump

ΔT

ΔTTime (ns)

X-raylaserTime (ns)laser
X-rayDVD disks

S. Kimura, Y. Tanaka et al. (JASRI, RIKEN)

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2/21-filling+18 bunches
228.1 ns

S. Kimura, Y. Tanaka et al. (JASRI, RIKEN)

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Today’s Topics• Univ. of Hyogo? Where is it?
• General aspects of pump/probe experiments• Laser/Synchrotron pump/probe experiments• FEL/Laser pump/probe experiments• Storage-Ring-FEL/SR pump/probe experiments

ExamplesLaser/FEL@FLASH (Germany)

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Experiments at FLASHFEL energy: X-rays
20fs, ~20 µJ/pulse.
Optical Laser:
800 nm or 400 nm,
130fs, 10µJ/pulse.
C. Gahl, A. Azima, M. Beye, M.Deppe, K. Döbrich, F.
Hennies, A. Melnikov, M. Nagasono, M. Wolf, W.
Wurth, A. Föhlisch
Nature Photonics (2008).

How to adjust timing between Laser and FEL?

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Synchronization of FEL and Laser at Spring-8

FEL RF 5712 MHz, 238 MHz, 79.3 MHz
Mode Locked Ti:Sapphire Laser with 79.3MHz+Amplifier (Chirp plus Amplifier, CPA)
=1 kHz

Today’s Topic• Univ. of Hyogo? Where is it?
• General aspects of pump/probe experiments• Laser/Synchrotron pump/probe experiments• FEL/Laser pump/probe experiments• Storage-Ring-FEL/SR pump/probe experiments

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UVSOR

Storage ring FEL at UVSOR
Optical cavity length = 13.3 m= ( Ring circumference)/4Electron Bunch

Electron Bunch

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Laser + SR

SRFEL + SR

Advantage
Advantage:High:Highenergy
energyresolution
resolution:Time-dependent:Time-dependentmeasurement
measurement

Advantage
Advantage:No:Nojitterjitter(Natural(Naturalsynchronization)synchronization):Higherphoton:Higher photonflux
flux(~1W)(~1W):Lasing
ispossible:Lasing is possiblewith
withwidewide
regionofwavelength
region of wavelength

UVSOR-II-FELの短波長化

1000
800

2007.9.10
199.3 nm

600
400
200
0-200
190

195
200
205
Wavelength (nm)21018

Introduction of pump/probe experiments

FEL

ExperimentSRFEL
SRFELat
atUVSORUVSOR
Wavelength
Wavelength
Intensity
Intensity
Frequency
Frequency

200-600
200-600nm
nm
MAX
MAX1.2W
1.2W((~100nJ)~100nJ)
10MHz10MHz

SampleSamplePump
Pump lightlightXe
Xe
Undulator
Undulatorlight
light ++LIF
LIFfilter
filterVUVVUV SRSR
ProbeProbe light
light FEL
FEL

Energy Diagram of Xe

Xe+ 5p 5 ( 2 p1/2 )13.4 eV12.6 eV

5p 5 ( 2 p1/2 )4f'[5/2]

12.1 eVXe+ 5p 5 ( 2 p3/2 )10.4 eVdecay:
t=600 psFEL

5p 5 ( 2 p3/2 )5d[3/2]11SR

Xe 5p 6 ( 1 S0 )Energy Diagram of Xe

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Imaging technique

Beam Nozzle

Repeller
Extractor

SR light

ＭＣＰ＋ＰＳＤ

FEL Transport
FEL Mirror

FEL Mirror
Optical Klystron

beam bunch
FELUndulator
beam bunch
Mirrorf = 100000m

5m

10 m

20

Future PlanFEL Mirror

FEL Mirror

13300+ 400

1850 mm

FELA

1250 mmbeam bunch
7560

Blue Poles( H: 1650 mm)

C

10000

START POINT

5870

END POINT
17154

7200

B
beam bunch

19 deg.

D13630A)
18192B)
SRQ1

New tabel( H: 1650 mm)

2000 F100500

E
DELAY: 60 ~ 660

A) Hight : 1850

2800

B) Hight : 1250

2800

BL7B

OpticsLaser size s (mm)54
f = 10 m

32laser waist
f = 2m10-100102030

Length from backward mirror (m)21Timing

LiF

Undulator light

Xe gasIn vacuum

Sampling
OpticalOscillosope

50
Intensity (a. u.)

Lens

FEL

FEL

Movableoptical delay stageSR
30

00510Time (nsec)

152022

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Synchronization of FEL and SR pulses

300x10340
Undulator
30
Intensity

200
150
100

FEL
2s = 0.472 ns

20
2s = 0.077 ns
1050

00-1.5-1.0-0.5

0.00.51.00123

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time (ns)timedelay (ns)Ion yield spectrum

120x10qsbsagx0

3100

Intensity

Intensity (count/sec)

250

80= 7.2509 ± 0.271= 29000 ± 0= 1891.4 ± 144= 3.9517 ± 0.122= 17540 ± 060
40

17.45

17.50

17.55

17.60

17.65x10

3

Wavenumber (1/cm)

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Ion yield spectrum with changing wavelength of SR

1000

800

600

5 10-4Torr
500u-500u
Intensity (counts/sec)

Intensity (counts/sec)

250
5 10-4Torr
2000u-2000u

200

150

100

400
50

200

0
116.5 117.0 117.5 118.0 118.5 119.0
Wavelength (nm)116.5 117.0 117.5 118.0 118.5 119.0
Wavelength (nm)Energy Diagram of Xe
Ｘｅ+５ｐ5（2Ｐ1/2）

FEL

５ｐ5（2Ｐ1/2）４ｆ‘｛5/2｝
Ｘｅ+５ｐ5（2Ｐ3/2）
５ｐ5（2Ｐ3/2）５ｄ｛３/2｝

SRFEL
SRSR
FEL

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Polarization effectIntensity (counts/sec)

50x10

3

VerticalHorizontal
Circular
Normal

40

30

20568

569570
FEL wavelength (nm)

571

572

Experiment with Q-switching FEL
0 ms
0 ns

50 ms

100 msFEL 1.9 ns

Event Gate26

Q-switching FEL
318x10Intensity (counts/sec)

1614

12108

6300x10

566

568

570
FEL wavelength (nm)

572

574

566

568

570
FEL wavelength (nm)

572

574

3

Intensity (counts/sec)

280

260

240

220

200

Today’s Topics• Univ. of Hyogo? Where is it?
• General aspects of pump/probe experiments• Laser/Synchrotron pump/probe experiments• Laser/FEL pump/probe experiments• Storage-Ring-FEL/SR pump/probe experiments

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