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
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
OUTLINE
Introduction Background Motivation
Theory Results
Long range Coulomb potential effects Intensity dependence for fixed wavelength
Conclusions
Background
fs 10nm 800400
laser pulse
atomAr
ionization of electron
intensity
pU
pI
)cos()(ˆ)( 0 ttazEtE
pp UIn
214 W/cm10~I
Background
p
p
U
I
2Keldysh parameter:
1
Multiphoton ionization
1
Tunneling ionization
Above-threshold-ionization (ATI)
)( 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
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
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
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
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
Effects of Coulomb Potential
P|| (a.u.) P|| (a.u.)
P
(a.u
.)
Exact TDSE TDSE for Rc=2
SFATDSE for Rc=8
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)
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
.)
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
.)
• Coulomb tail effects are crucial for slow photoelectrons
• Volume effects has to be taken into account when compare theory with experiment
Conclusion
Thank You !
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
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)
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
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
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
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
