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Detector
1
h 0 v Detector F ion z 0 Christophe Blondel, Christian Delsart, Cyril Drag & Ramón J. Peláez Laboratoire Aimé-Cotton, Centre national de la recherche scientifique, bâtiment 505, université Paris-sud, F-91405 Orsay cedex, France Photodetachment microscopy with a pulsed laser and sub-meV ponderomotive effects Experimental set-up qF a 0 max 2 az R 2 3 0 3 2 a N Interfringe interval a z N R i 3 0 0 max 3 a z R Ai R j 0 2 0 2 4 1 ) ( Single-mode pulsed laser Ponderomotive effects observed in O - 7 6 5 4 3 2 1 8 9 10 11 12 13 1 : Source and simple lens doublet (“Einzellens") 2,5,9,10 : Deflection plates 3,6,8 : Simple lenses 4 : Wien velocity filter 7 : Deflection quadrupole 11 : Focalisation quadrupole 12 : Deceleration plates 13 : Interaction zone C D F U Freq. doubled Q-CW Yb:YAG 515 nm - 20 Hz quasi-CW Ti:Sa 150 µs Dual polarization stabilized He-Ne Sigmamete r WSU lambdameter uncertainty : +/-0.041 m -1 Frequency- doubled Nd:YAG 25 mJ @ 532 nm Pulsed Ti:Sa ~ 10 mJ @ 848 nm L. Cabaret and C. Drag, Eur. Phys. J. Appl. Phys. 37 (2006) 65 L. Cabaret, Appl. Phys. B 94 (2009) 71 Quantum parameters : Wavelength scale Number of rings Classical parameters Radial current density Principle: Y.N. Demkov et al., JETP Lett. 34 (1981) 403 Photodetachment microscopy: C. Blondel et al., Phys. Rev . Lett. 77 (1996) 3755 Photoionization microscopy: C. Nicole et al., Phys. Rev . Lett. 88 (2002) 133001 Molecular photodetachment microscopy : F. Goldfarb et al., J. Chem. Phys. 122 (2005) 014308 Photodetachment microscopy in a magnetic field : W. Chaibi et al., Eur., Phys. J. D 58 (2010) 29 Highest height Maximum radius 3 2 0 2 mqF 14 15 14 : Pulsed Ti:Sa laser 15 : Column of constant F 16 : MCP 17 : Phosphor screen 18 : CCD negativ e ion neutral atom h e A 18 1 6 17 Accumulation Barycenter Photodetachment microscopy 2 ' 2 1 2 1 U F C D h A Single longitudinal mode Short & long term stabilized (+/- 20 MHz for 100 min) Pulse duration ≈ 25 ns Energy ≈ 3- 10 mJ Main properties PAMO 2010 and ECAMP X Radius (arbitrary unit) Radius (arbitrary unit) Radius (arbitrary unit) Photocurrent (arbitrary unit) Photocurrent (arbitrary unit) Photocurrent (arbitrary unit) 0 200 400 600 800 1000 1200 0 10 20 30 40 50 EXP FIT OD = 0 0 50 100 150 200 250 300 350 400 450 0 10 20 30 40 50 EXP FIT OD = 0.4 0 20 40 60 80 100 120 0 10 20 30 40 50 EXP FIT OD = 1 The number of interference rings decreases when the optical density decreases, i.e. when the laser peak intensity increases. At the peak intensity, the energy shift revealed in this way would be -0.27 cm - 1 /mJ, but the observed effect appears attenuated by the three-dimensional integration on the whole interaction volume and the pulse duration. Photodetachment images obtained on O - with attenuation by an optical density OD between 1 and 0. a R F = 427 Vm - 1 R max j 0 = 0.045 m a = 0.35 m = 0.926 ± 0.002 cm -1 Tunable (250 m -1 ) 2-Oct-2009 y = -0.0255x + 0.5601 R 2 = 0.973 0.42 0.45 0.48 0.51 0.54 0.57 0.60 0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.50 4.00 Plaser(m J) Energy (cm -1 ) E laser (mJ) Photoelectron energy as a function of the laser pulse energy Presence of an EM field reduces the “free” electron kinetic energy by U p =q 2 E 2 /4m 2
description
D. F. 7. C. 8. U. 6. 1 : Source and simple lens doublet (“Einzellens") 2,5,9,10 : Deflection plates 3,6,8 : Simple lenses. 10. 4. 5. 12. 2. 4 : Wien velocity filter 7 : Deflection quadrupole 11 : Focalisation quadrupole 12 : Deceleration plates 13 : Interaction zone. - PowerPoint PPT Presentation
Transcript of Detector
h 0v
Detector
Fion
z0
Christophe Blondel, Christian Delsart, Cyril Drag & Ramón J. Peláez
Laboratoire Aimé-Cotton, Centre national de la recherche scientifique, bâtiment 505, université Paris-sud, F-91405 Orsay cedex, France
Photodetachment microscopy with a pulsed laser and sub-meV
ponderomotive effects
Experimental set-up
qFa
0max2azR
23
032
aN
Interfringeinterval
a
z
NR
i3
00max 3
a
zRAiRj
0
2
0
2
41)(
Single-mode pulsed laser
Ponderomotive effects observed in O-
7
6
5 4
3
2
1
8
9
10
11
12
13
1 : Source and simple lens doublet (“Einzellens") 2,5,9,10 : Deflection plates3,6,8 : Simple lenses
4 : Wien velocity filter7 : Deflection quadrupole 11 : Focalisation quadrupole 12 : Deceleration plates13 : Interaction zone
C
D
F
U
Freq. doubled Q-CWYb:YAG 515 nm - 20 Hz
quasi-CW Ti:Sa
150 µs
Dual polarization
stabilized He-Ne
Sigmameter
WSU lambdameter uncertainty: +/-0.041 m-1
Frequency-doubled Nd:YAG 25 mJ @ 532 nm
Pulsed Ti:Sa~ 10 mJ @ 848 nm
L. Cabaret and C. Drag, Eur. Phys. J. Appl. Phys. 37 (2006) 65
L. Cabaret, Appl. Phys. B 94 (2009) 71
Quantum parameters :
Wavelength scale
Number of rings
Classical parameters
Radial current density
Principle:Y.N. Demkov et al., JETP Lett. 34 (1981) 403
Photodetachment microscopy:C. Blondel et al., Phys. Rev . Lett. 77 (1996) 3755
Photoionization microscopy:C. Nicole et al., Phys. Rev . Lett. 88 (2002) 133001
Molecular photodetachment microscopy :F. Goldfarb et al., J. Chem. Phys. 122 (2005) 014308
Photodetachment microscopy in a magnetic field :W. Chaibi et al., Eur., Phys. J. D 58 (2010) 29
Highest height
Maximum radius
32
0 2mqF
14
15
14 : Pulsed Ti:Sa laser15 : Column of constant F16 : MCP17 : Phosphor screen18 : CCD
negative
ion
neutral atom
h
eA
18
16
17
Accumulation Barycenter
Photodetachment microscopy
2
'
2
1
21
U
F
C
DhA
Single longitudinal mode
Short & long term stabilized
(+/- 20 MHz for 100 min)
Pulse duration ≈ 25 ns
Energy ≈ 3- 10 mJ
Main properties
PAMO 2010 and ECAMP X
Radius (arbitrary unit)
Radius (arbitrary unit)
Radius (arbitrary unit)
Photo
curr
ent
(arb
itra
ry
unit
)Photo
curr
ent
(arb
itra
ry
unit
)Photo
curr
ent
(arb
itra
ry
unit
)
0
200
400
600
800
1000
1200
0 10 20 30 40 50
EXP
FIT
OD = 0
0
50
100
150
200
250
300
350
400
450
0 10 20 30 40 50
EXP
FIT
OD = 0.4
0
20
40
60
80
100
120
0 10 20 30 40 50
EXP
FIT
OD = 1
The number of interference rings decreases when the optical density decreases, i.e. when the laser peak intensity increases. At the peak intensity, the energy shift revealed in this way would be -0.27 cm-1/mJ, but the observed effect appears attenuated by the three-dimensional integration on the whole interaction volume and the pulse duration.
Photodetachment images obtained on O- with attenuation by an optical density OD between 1 and 0.
a
R
F = 427 Vm-
1
Rmax
j
0 = 0.045 ma = 0.35 m
= 0.926 ± 0.002 cm-1
Tunable (250 m-
1)
2-Oct-2009
y = -0.0255x + 0.5601
R 2 = 0.973
0.42
0.45
0.48
0.51
0.54
0.57
0.60
0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.50 4.00
Plaser (mJ)
En
erg
y (c
m-1
)
Elaser (mJ)
Photoelectron energy as a function of the laser pulse energy
Presence of an EM field reduces the “free” electron kinetic energy by Up=q2E2/4m2
