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