2d momentum spectra of the ati electrons by 10 fs laser pulses
DESCRIPTION
2D Momentum Spectra of the ATI Electrons by 10 fs Laser Pulses. Zhangjin Chen Advisor: C. D. Lin Collaborators: Marlene Wickenhauser, A. T. Le and X. M. Tong Department of Physics Kansas State University. OUTLINE. Introduction Background Motivation Theory Results - PowerPoint PPT PresentationTRANSCRIPT
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2D Momentum Spectra of the ATI Electrons by 10 fs Laser Pulses
Zhangjin Chen
Advisor: C. D. Lin
Collaborators:Marlene Wickenhauser, A. T. Le and X. M. Tong
Department of PhysicsKansas State University
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OUTLINE
Introduction Background Motivation
Theory Results
Long range Coulomb potential effects Intensity dependence for fixed wavelength
Conclusions
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Background
fs 10nm 800400
laser pulse
atomAr
ionization of electron
intensity
pU
pI
)cos()(ˆ)( 0 ttazEtE
pp UIn
214 W/cm10~I
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Background
p
p
U
I
2Keldysh parameter:
1
Multiphoton ionization
1
Tunneling ionization
Above-threshold-ionization (ATI)
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)( pp UInE )(0 0 pp UIn
Wickenhauser et al: PRA 73, 011401(R) (2006)
ħω
Bucksbaum et al: PRA 37, 3615(R) (1988)
He
ps 8 nm 532
W/cm102.3I 214
ATI peaks
fs 10 nm 400
W/cm101.7I 214
Ar
Background
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Motivation
x
y
C.M. Marhajan, A. Alanser, ...,C.L. Cocke et al. (submitted)E
Low energy spectra: lots of structure even in tunneling regime
z
atom
e
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Theory
' i"2
)]"([ iexp
)]'([)'(' i)(
'
2
tIdttAp
tApdtEdtpb
pt
)(0 rVTH eff
),()]([),()(),( 0 trtVHtrtHtrt
i
Dipole transition moment
Laser-dressed energy
Strong field approximation (SFA)Numerical solution of TDSE
Split operator method for time propagation
X.M. Tong and Shih-I Chu: Chem Phys 217, 119 (1997) M. Lewenstein et al: PRA 49, 2117 (1994)
rtEtV
)()(
Single active electron approximation
)(),()2/exp(
])2/,,(exp[
)2/exp(),(
30
0
tOtrtiH
tttrV
tiHttr
Neglect: -Coulomb field on ionized electrons -Depletion of ground state
-Other bound states
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0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30-20
-18
-16
-14
-12
-10
-8
-6
-4
-2
0
2
V(r
)*r
(a.u
.)
r (a.u.)
Exact potential R
c=8
Effects of Coulomb Potential
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Exact TDSE
TDSE for Rc=8
TDSE for Rc=5
TDSE for Rc=2
SFA
P|| (a.u.)
P
(a.u
.)
P
(a.u
.)P|| (a.u.)
Effects of Coulomb Potential
214 W/cm1005.2 nm 500
Ip=15.759 eV
Ip=15.759 eV
Ip=15.759 eV
Ip=15.612 eV
36.1
36.0 9 1 pneV 54.20
eV 08.19475.28
pp IU
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Effects of Coulomb Potential
P|| (a.u.) P|| (a.u.)
P
(a.u
.)
Exact TDSE TDSE for Rc=2
SFATDSE for Rc=8
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Volume Effect
z
x
y
)(tan)(tan3
4
9
)(4
3
)(4
21
11
32
31212
0
cc
cccczV R
II
VIP
dIdI
dVIPdVIPP
)(
)()(
2/10 ]/)[( jjj IIIc
Peak Laser Intensity
Rayleigh range of the focus
S Augst et al: J. Opt. Soc. Am. B 8, 858 (1991)
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Intensity dependencea.u. 28.01 p
a.u. 25.01 p
a.u. 21.01 p
a.u. 17.01 p
214 W/cm1013.1 I
214 W/cm1020.1 I 214 W/cm1034.1 I
214 W/cm1027.1 I600 nm, n=10 600 nm, n=10
600 nm, n=10600 nm, n=10
P|| (a.u.) P|| (a.u.)
P
(a.u
.)
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a.u. 17.01 p
214 W/cm1034.1 I 600 nm, n=10
214 W/cm1046.1 I
214 W/cm1040.1 I 214 W/cm1053.1 I
214 W/cm1060.1 I
a.u. 34.01 pa.u. 39.01 p
a.u. 36.01 pa.u. 11.01 p
600 nm, n=11
600 nm, n=10 600 nm, n=11
600 nm, n=11
Intensity dependence
P|| (a.u.) P|| (a.u.)
P
(a.u
.)
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• Coulomb tail effects are crucial for slow photoelectrons
• Volume effects has to be taken into account when compare theory with experiment
Conclusion
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Thank You !
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OUTLINE
Introduction Background Motivation
Theory Results
Long range Coulomb potential effects Wavelength dependence for fixed Keldysh parameter Wavelength dependence for fixed 1st peak position Intensity dependence for fixed wavelength
Conclusions
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Background
P|| (a.u.)
P|| (a.u.)-1 -0.5 0 0.5 1
~ 1.76
-1 -0.5 0 0.5 1
0
0
.5
1
P|| (a.u.)
~ 0.89
0
0
.5
1
214 W/cm107.1 nm 400 214 W/cm1065.1 nm 800
Wickenhauser et al: PRA 73, 011401(R) (2006)
0
0
.3
0.6
0
0
.3
0.6
P
(a.u
.)P
(ar
b un
its)
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28.1
400 nm, n=7
500 nm, n=9
600 nm, n=10
700 nm, n=12
Wavelength dependence for fixed
a.u. 30.01 p
a.u. 36.01 p
a.u. 09.01 p
a.u. 22.01 p
P|| (a.u.) P|| (a.u.)
P
(a.u
.)
214 W/cm1020.3 I
214 W/cm1005.2 I
214 W/cm1042.1 I
214 W/cm1005.1 I
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Wavelength dependence for fixed 1p
a.u. 285.01 pP|| (a.u.) P|| (a.u.)
P
(a.u
.)
400 nm, n=7
500 nm, n=9
600 nm, n=11
700 nm, n=13
214 W/cm1020.3 I 214 W/cm1073.1 I
214 W/cm1031.2 I 214 W/cm1034.1 I
28.1
21.1 13.1
16.1
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I λ Up Up+Ip γ n nһω p-1
3.200 400 4.7770 20.5366 1.2843 7 21.6580 0.3
2.050 500 4.7816 20.5412 1.2837 9 22.2768 0.36
1.420 600 4.7695 20.5291 1.2853 10 20.6267 0.085
1.050 700 4.8003 20.5599 1.2812 12 21.2160 0.22
0.800 800 4.7770 20.5366 1.2843 14 21.6580 0.287
Fixed Keldysh parameter
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Intensity wavelength Up Up+Ip gamma n nw k first peak (eV)
Energy of photon=3.094000 eV3.200 400 4.7770 20.5366 1.2843 7 21.6580 0.2872
1.12
Energy of photon=2.475200 eV2.310 500 5.3881 21.1477 1.2093 9 22.2768 0.2881
1.13
Energy of photon=2.062667 eV1.730 600 5.8107 21.5703 1.1645 11 22.6893 0.2868
1.12
Energy of photon=1.768000 eV1.340 700 6.1261 21.8857 1.1341 13 22.9840 0.2842
1.10
Fixed 1st peak position
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