keV HHG and Sub femtosecond K-shell excitation.

( using IR (2.1m) Radiation Source )

Gilad Marcus

The Department of Applied Physics, The Hebrew University, Jerusalem, Israel

Tel Aviv, 2-4, December 2013

Acknowledgment

Xun Gu 1

Wolfram Helml 1

Yunpei Deng 1• Ferenc Krausz 1

• Reinhard Kienberger 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

• Currently, the photon energy of atto-second pulses is limited to ~150 eV ( l~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 resolution

Motivation for keV HHG

Increasing the energy of the re-colliding electrons

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

By using a longer wavelengthwe can overcome the ionizationproblem

• Currently, the photon energy of atto-second pulses is limited to ~150 eV ( l~8 nm).

The 2-cycles IR source

15 fsec740 µJ1 kHz

Self CEP Stabilization

nm

OPA system output: Carrier wave-length: =l 2.1mmPulse 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 (2.1mm) 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.

High Harmonic Generation

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 excitation

THG FROG

compressor(bulk silicon)

Diagnostics for pulse compression measurement

THG FROG

focusing lens(CaF2, 250 mm)

keV 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

Photon counting and photon’s energy resolving with the pnCCD

Two photons hittingtwo pixels.

The charge in each pixel is proportionalto the photon energy

Photon counting and photon’s energy resolving with the pnCCD

Charge from one photons, spilled into neighboring pixels

Photon counting and photon’s energy resolving with the pnCCD

Rejected as an error.Not a reasonable charge distribution

Cosmic ray trace

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

1.6 keVCut off

G. Marcus, et. al, PRL 108, 023201.

Photon counting and photon’s energy resolving with the pnCCD

Two photons hittingtwo pixels.

The charge in each pixel is proportionalto the photon energy

Photon counting and photon’s energy resolving with the pnCCD

Real spectrum

Two pixels pseudo photons

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

1.6 keVCut off

G. Marcus, et. al, PRL 108, 023201.

keV high harmonics and K-shell excitation

500 1000 150010

0

102

104

106

108

1010

Spectrum from Ne Target

photons energy [eV]

cou

nts

/ b

in

100 200 300 400 500 600

102

104

106

Spectrum from N2 Target

photons energy [eV]

cou

nts

/ b

in

Ne K-edge

NitrogenK-edge

keV high harmonics and K-shell excitation

Enhanced peak at the K-edge

Better phase matching conditionsdue to the absorption lines

Inner shell excitation followed by x-ray emission

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-edge

Calculation shows: Plasmadispersion still dominate

Inner shell excitation followed by x-ray emission

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-edge

Inner shell excitation followed by x-ray fluorescence

keV high harmonics and K-shell excitation

Enhanced peak at the K-edge

Inner shell excitation followed by x-ray fluorescence

2exdP ( ) / ( )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-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-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-edge

Inner shell excitation followed by x-ray fluorescence

x 0edP ( ) ( ) ( ) ( )i

i i

t

t t dt v v d

2D

eab

0x

S1 expA dP

4rad

av LA

abu

Ld

f

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

Inner shell excitation followed by x-ray fluorescence

Thank you