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Sub femtosecond K-shell excitation using Carrier Envelop Phase Stabilized 2-Cycles IR
(2.1m) Radiation Source.
Gilad Marcus
The Department of Applied Physics, Hebrew University,Jerusalem, Israel
FRISNO 12, Ein Gedi 2013
AcknowledgmentAcknowledgment
Xun Gu 1
Wolfram Helml 1
Yunpei Deng 1
• Reinhard Kienberger 1
• Ferenc Krausz 1
• Robert Hartmann 2
• Takayoshi Kobayashi 3
• Lothar Strueder 4
1. Max Planck, Quantum Optic, Germany2. pnSensor GmbH, Germany3. University of Electro-Communications, Chofu, Tokyo,
Japan4. Max Planck, Extraterrestrial Physics, Germany
Outlines
Introduction (defining the goal)
The IR OPCPA system
keV high harmonics
2 2kin 2
max W 3.17 , 4p p
e L
eEU U I
m
High Harmonics the 3 steps model
plateau
cut-offx
uv
TL
Re-collision Processes
Double ionization / excitation
Elastic scattering
Discrete electron spectrum
High Harmonics
High harmonics spectra
• Currently, the photon energy of atto-second pulses is limited to ~150 eV ( ~8 nm).
Pushing the HHG toward the x-ray regime Shorter attosecond pulses Access to the water-window (300-500 eV) Time resolved spectroscopy of inner-shell processes X-ray diffraction imaging with a better resolution
Re-colliding electrons with higher energies Laser induced diffraction imaging with better time and space
resolution (elastic scattering) Efficient Inner-shell excitation (inelastic scattering)
Motivation for keV HHG
Pushing atto-tools toward higher energiesby using a longer wavelength
I (PW/cm2)
0.15 0.5 1.0
λ (nm) 800 2100 800 2100 800 2100
Up (eV) 9.0 61.8 30 206 60 412
ħωmax (eV)
44 211 110 668 205 1321
2pU I
Ion yield of Xe vs. Laser intensity
Few-cycles Pulse
Recombination emission:soft-X-ray photon emission upon the electron recombining into its ground state
Ionizationthreshold
Cosine waveform
Emission ofhighest-energy photon
( ) cos CEPE f t t
Few-cycles Pulse
Ionizationthreshold
Sine waveform
Emission ofhighest-energy photons
Recombination emission:soft-X-ray photon emission upon the electron recombining into its ground state
( ) cos2
E f t t
The 2-cycles IR source
15 fsec740 µJ1 kHz
Self CEP Stabilization
nm
OPA system output: Carrier wave-length: 2.1mPulse duration: 15.7 fs (2 cycles)Pulse energy: 0.7 mJRep rate: 1000 Hz Automatically Carrier-envelope-phase-stabilized
wav
elen
gth,
nm
f-to-3f interferogram
2 cycles IR (2.12 cycles IR (2.1m) sourcem) source
Long term (few hours) phase scanB.Bergues, et. al, New Journal of Physics 13, no. 6 ( 2011): 063010.
I. Znakovskaya, et al. PRL 108, no. 6 (2012): 063002.
THG FROG
compressor(bulk silicon)
Diagnostics for pulse compression measurement
THG FROG
focusing lens(CaF2, 250 mm)
High harmonic beam from N2
through 150nm Pd +500nm C
Ne/N2 gas target,pressure up to 3 bar!
PNCamera
keV high harmonics and K-shell excitationkeV high harmonics and K-shell excitation
THG FROG
compressor(bulk silicon)
Diagnostics for pulse compression measurement
THG FROG
focusing lens(CaF2, 250 mm)
keV high harmonics and K-shell excitationkeV high harmonics and K-shell excitation
High harmonic beam from N2
through 150nm Pd +500nm C
Ne/N2 gas target,pressure up to 3 bar!
PNCamera
keV high harmonics and K-shell excitation
500 1000 15000
10
20
30
40
50
60
photons energy [eV]
cou
nts
/ b
in
500 1000 15000
10
20
30
40
50
60
photons energy [eV]
cou
nts
/ b
in
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
tran
smis
sio
n
0
0.1
0.2
0.3
0.4 (b)(a)
500 1000 15000
10
20
30
40
50
60
photons energy [eV]
coun
ts /
bin
500 1000 15000
10
20
30
40
50
60
photons energy [eV]
coun
ts /
bin
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
tran
smis
sion
0
0.1
0.2
0.3
0.4 (b)(a)
High harmonics spectrum from a neon gas target through 500nm aluminum
Same spectrum through additional 500nm of vanadium (a) or iron (b)
Vanadium L-edge Iron L-edge
200 400 600 800 1000 1200 1400 1600 1800 2000 220010
0
101
102
103
104
photons energy [eV]
co
un
t /
bin
HHG (Ne)T (3bar Ne)T (500nm Al)
10-3
10-2
10-1
100
tra
ns
mis
sio
n
keV high harmonics and K-shell excitation
500 1000 150010
0
102
104
106
108
1010
Spectrum from Ne Target
photons energy [eV]
co
un
ts /
bin
100 200 300 400 500 600
102
104
106
Spectrum from N2 Target
photons energy [eV]
co
un
ts /
bin
Ne K-edge
NitrogenK-edge
keV high harmonics and K-shell excitation
Enhanced peak at the K-edgeEnhanced peak at the K-edge
Better phase matching conditionsdue to the absorption lines
Inner shell excitation followed by x-ray fluorescence
0.5 1 1.5
0
0.5
1
/0
Re(n)Im(n)
keV high harmonics and K-shell excitation
Enhanced peak at the K-edgeEnhanced peak at the K-edge
Calculation shows: Plasmadispersion still dominate
Inner shell excitation followed by x-ray fluorescence
0.5 1 1.5
0
0.5
1
/0
Re(n)Im(n)
keV high harmonics and K-shell excitationkeV high harmonics and K-shell excitation
Enhanced peak at the K-edgeEnhanced peak at the K-edge
Inner shell excitation followed Inner shell excitation followed by x-ray fluorescenceby x-ray fluorescence
keV high harmonics and K-shell excitation
Enhanced peak at the K-edgeEnhanced peak at the K-edge
Inner shell excitation followed by x-ray fluorescence
2exP ( ) / ( )i it D t dt
2D
0exab
1 expS
A P4
radav L
Aa
ub
ddt f L
0
rad Au
- in-elastic excitation cross section
D - electron wave packed radius
- ionization rate
- gas density
, - dacay rates (radiation , Auger)
keV high harmonics and K-shell excitation
Enhanced peak at the K-edgeEnhanced peak at the K-edge
Inner shell excitation followed by x-ray fluorescence
2exP ( ) / ( )i it D t dt
2D
0exab
1 expS
A P4
radav L
Aa
ub
ddt f L
0 1 2 3 4
0
16
32
48
64
80
pressure [bar]
ph
oto
n y
ield
0 1 2 3 40
20
40
60
80
100
120
140
160
180
pressure [bar]
ph
oto
n y
ield
[c
ou
nts
/ s
ec
]
keV high harmonics and K-shell excitation
Enhanced peak at the K-edgeEnhanced peak at the K-edge
Inner shell excitation followed by x-ray fluorescence
2exP ( ) / ( )i it D t dt
2D
0exab
1 expS
A P4
radav L
Aa
ub
ddt f L
0 1 2 3 4
0
16
32
48
64
80
pressure [bar]
ph
oto
n y
ield
0 1 2 3 40
20
40
60
80
100
120
140
160
180
pressure [bar]
ph
oto
n y
ield
[c
ou
nts
/ s
ec
]
keV high harmonics and K-shell excitation
Enhanced peak at the K-edgeEnhanced peak at the K-edge
Inner shell excitation followed by x-ray fluorescence
0exP ( ) ( ) ( ) ( )i
i i
t
t t dt v v d
2D
0exab
1 expS
A P4
radav L
Aa
ub
ddt f L
0 1 2 3 4
0
16
32
48
64
80
pressure [bar]
ph
oto
n y
ield
0 1 2 3 40
20
40
60
80
100
120
140
160
180
pressure [bar]
ph
oto
n y
ield
[c
ou
nts
/ s
ec
]
0 0.5 1 1.5 2 2.5 3 3.5 40
50
100
150
pressure [bar]
phot
on y
ield
0 2 4
0
2
4
keV high harmonics and K-shell excitation
Enhanced peak at the K-edgeEnhanced peak at the K-edge
Inner shell excitation followed by x-ray fluorescence
0exP ( ) ( ) ( ) ( )i
i i
t
t t dt v v d
2D
0exab
1 expS
A P4
radav L
Aa
ub
ddt f L
0 1 2 3 4
0
16
32
48
64
80
pressure [bar]
ph
oto
n y
ield
0 1 2 3 40
20
40
60
80
100
120
140
160
180
pressure [bar]
ph
oto
n y
ield
[c
ou
nts
/ s
ec
]
0 0.5 1 1.5 2 2.5 3 3.5 40
50
100
150
pressure [bar]
phot
on y
ield
0 2 4
0
2
4
keV high harmonics and K-shell excitationkeV high harmonics and K-shell excitation
Inner shell excitation followed by x-ray fluorescence
Pump laser pulseDuration 12 fs
Intensity 7x1014 W/cm2
m
Thank youThank you