1. Frontier Research @ FERMI
C. Masciovecchio
Elettra - Sincrotrone Trieste, Basovizza, Trieste I-34149
Introduction to FERMI Free Electron Laser
The Experimental End-Stations
EIS program (TIMEX & TIMER)
MULTICOLOR Spectroscopy

2. Why Free Electron Lasers?
“ Boeing has won a U.S. Navy contract worth up to $163 million to develop the Free Electron Laser (FEL), a weapon system that the company says "will transform naval warfare in the next decade by providing an ultra-precise, speed-of-light capability and unlimited magazine depth to defend ships against new, challenging threats, such as hyper-velocity cruise missiles." The envisioned level of precision would enable U.S. Navy ships to deliver nonlethal or lethal force to targets with power and minimal collateral damage………
FEL technology is considered by the US Navy as a promising technology for an antimissile directed-energy weapon. A directed-energy weapon (DEW) is a type of weapon that emits energy in an aimed direction without the means of a projectile- like an intense emission of laser light. FEL’s are capable of achieving the megawatt power level the Navy requires for ship defense. “

3. Why Free Electron Lasers?
Leonard comes home...and promptly passes out on the couch. The reason wasn't a good night on the town, however. It was the fact that he's working nights using the free-electron laser to conduct his X-ray diffraction experiment.

4. X-ray Diffraction Experiments
obtain an adequate crystal of the material under study. It should be sufficiently large (typically > 0.1 mm), pure in composition and regular in structure.
it is placed in an intense beam of X-rays, usually of a single wavelength (monochromatic X-rays), producing the regular pattern of reflections. As the crystal is gradually rotated, previous reflections disappear and new ones appear; the intensity of every spot is recorded at every orientation.
these data are combined computationally with complementary chemical information to produce and refine a model of the arrangement of atoms within the crystal. The final, refined model of the atomic arrangement (the crystal structure) is stored in public databases.
PROTEINS  To understand the functions of proteins at a molecular level, it is necessary to determine their three-dimensional structure

5. X-ray Diffraction Experiments
Many biological specimens such as whole cells, cellular organelles, some viruses, and many important protein molecules are difficult or impossible to crystallize and hence their structures are not accessible by crystallography
For example: as of January 2016 less than 0.1% of protein structures determined were membrane proteins despite being 20-30% of the total proteome.

6. Coherent diffraction imaging
Incoherent illumination
average over patterns resulting from slightly different wavefronts
Coherent illumination
information on the positions of all particles, and these positions are obtained inverting the pattern

7. CDI at Synchrotron

8. 3D Imaging of Yeast Cell at Synchrotron
3D quantitative imaging of a whole, unstained yeast spore at a resolution of 50–60 nm
H. Jiang, et al, PNAS, 107, (2010).

9. What are the Problems?

10. What are the Solutions?

11. X-ray Diffraction Experiments
R. Neutze et al, Nature (2005)

12. Time resolved Imaging: the dream
Goal: snapshots on the atomic space (nm) and time (fs) length-scales

13. Why Free Electron Lasers ?
Peak brilliance = photons/s/mrad2/mm2/0.1%bandwidth
~ 3·106 diffraction patterns (100 TB) from photosystem I protein nanocrystals.

14. Why Free Electron Lasers ?
Pulse Duration
100 nm
1ns
1ps
10ps
100ps
1fs
10fs
100fs
1μm
10nm
1 nm
1 A
1eV
10eV
100eV
1keV
10keV
Synchrotron radiation
Conventional lasers
LPE FELs
HPE FELs
HHG in gases
Plasma lasers
Imaging with high Spatial Resolution (~ l): fixed target imaging, particle injection imaging,..
Dynamics: four wave mixing (nanoscale), warm dense matter, extreme condition, ....
Resonant Experiments: XANES (tunability), XMCD (polarization), chemical mapping, ……

15. Free Electron Lasers SASE (Self Amplified Spontaneous Emission)
LCLS (Stanford - USA)
XFEL (Hamburg - Germany)
SCSS (Jaery Riken - Japan) .
FLASH (Hamburg - Germany)

16. SASE vs Seeded
x 105
L. H. Yu et al., 91, PRL (2003)

17. FERMI
FEL 1
FEL 2

18. Dt < 100 fs Flux ~ 1013 ph/pulse E ~ 10 - 500 eV Total Control on
E. Allaria et al., Nat. Phot. (2012)
Dt < 100 fs
Flux ~ 1013 ph/pulse
E ~ eV
Total Control on
Pulse Energy
Time Shape
Polarization

19. FERMI – Photons/Pulse

20. DIPROI (DIffraction & PROjection Imaging) LDM (Low Density Matter)
The Experimental Hall
Commissioning
F. Bencivenga et al., J. Synch. Rad. (2015)
TIMER
TIMEX
C. Masciovecchio et al., J. Synch. Rad. (2015)
DIPROI (DIffraction & PROjection Imaging)
LDM (Low Density Matter)
C. Svetina et al., J. Synch. Rad. (2015)
F. Capotondi et al., J. Synch. Rad. (2015)
MagneDYN (Magnetic Dynamics)
TeraFERMI (THz beamline)

21. The Experimental Hall
TIMEX
DIPROI
LDM
TIMER

22. Pump & Probe
The pump pulse produces a change in the sample
stimulate a chemical reaction
non-equilibrium states
extreme thermodynamic conditions
ultrafast demagnetization
coherent excitations
Signal
that is monitored by the probe pulse
WORLD RECORD !!
GaAs
20 mm
Jitter ~ 5 fs
M. Danailov et al., Opt. Exp. (2014)

23. Ultrafast Magnetic Dynamics
DIPROI
Ultrafast Magnetic Dynamics
Co/Pt ML
C. von Korff Schmising, S. Eisebitt et al, PRL (2014)
Controlling ultrafast demagnetization using localized optical excitation

24. DIPROI X-ray holography with customizable reference
A. Martin et al. (2014)
X-ray holography with customizable reference
Ideal FTH  overcoming restriction due to the reference wave  single-shot imaging
Sample
Diffraction
Known reference
Hologram refined with RAAR phase retrivial
Conjugate-gradient algorithm to recover the image
FTH with an almost unrestricted choice for the reference
Longitudinal coherence matters!!

25. Coherent control at the attosecond time scale
LDM
Coherent control at the attosecond time scale
K. Prince et al., Nat. Phot. In press
Interference effect among quantum states using single and multiphoton ionization
C. Chen et al., PRL (1990)
Intensity = | M1 + M2(ϕ)| = | M1|2 + |M2(ϕ)|2 + 2 Re(M1 M2(ϕ))
Use of first ( eV ) and second harmonic on 2p54s resonance of Ne
Change of the phases among the two harmonics ‘invented’ by Allaria et al.,
Signal detected as function of phase on the VMI detector
Control of the phase among the two pulses!

26. Coherent control at the attosecond time scale
User beamtime Dec K.C. Prince
Ne irradiated with  26.9 and 53.8 eV 1 2 3 4
kinetic energy
Ne 2s 2w
Ne 2p w
2s22p5 w
2s12p6
2s22p6 + w + 2w  2s12p6 + e + w  2s22p5 + e + 2w (stimulated emission)
2s22p6 + w  2s22p5 + e
1  coherently controlled Ne 2s/2p
2 3 4 are doubly ionized states
2 and 3 oscillate 4 does not
2p and 2s electrons emitted with = kinetic energy
 the intense first harmonic entangles the holes

27. Elastic and Inelastic Scattering (EIS)
The Sample Side
Short pulses with very high peak power
Dt ~ 100 fs ; Peak Power ~ 5 GW ; E ~ 100 eV
Non-equilibrium distribution of electrons
What happens to the Sample?
Converge (electron-electron & electron-phonon collisions) to equilibrium (Fermi-like)
The intensity of the FEL pulses will determine the process to which the sample will
undergo: simple heating, structural changes, ultrafast melting or ultrafast ablation
TIMER
TIMEX
interior of large planets and stars

28. F. Bencivenga et al., (2014)
TIMEX
TIme-resolved studies of Matter under EXtreme and metastable conditions
Pump & Probe FEL Ti

29. TIMEX Ultrafast changes in the Electronic Structure of Ti
DOS variation
Empty Electronic States
Probability Distr. variation
Principi et al., Struct. Dynamics (2016)

30. TIMEX
K. Sokolowski-Tinten et al., J of Phys: Cond. Matt. (2004)
Time-resolved X-ray diffraction is sensitive to the long-range order and therefore to the melting
but does not probe the short range order that finally affects the DOS
Time-resolved X-ray absorption does probe the short range order
low density liquid (LDL) phase with a tetrahedral local structure appears after 300 fs and survives for about 1 ps
E. Giangrisostomi et al., to be submitted

31. w (meV) BLS IXS IUVS INS EIS - TIMER TIMER Q ( nm ) nano-scale
TIME-Resolved spectroscopy of mesoscopic dynamics in condensed matter
Challenge: Study Collective Excitations in Disordered Systems in the Unexplored w-Q region
w = cs·Q
Q (q) q
Determination of the Dynamic Structure Factor: S(Q,w)
Q ( nm -1 )
w (meV) -4 10 -3 -2 1 2 V
= 500 m/s
= 7000 m/s
BLS
INS
BL30/21
IXS
IUVS
BL10.2
nano-scale
atomic-scale
macro-scale

32. Why Disordered Systems ?
Unsolved problems in physics
Condensed matter physics
Amorphous solids
What is the nature of the transition between a fluid or regular solid and a glassy phase? What are the physical processes giving rise to the general properties of glasses?
High-temperature superconductors
What is the responsible mechanism that causes certain materials to exhibit superconductivity at temperatures much higher than around 50 Kelvin?
Sonoluminescence
What causes the emission of short bursts of light from imploding bubbles in a liquid when excited by sound?
Turbulence
Is it possible to make a theoretical model to describe the statistics of a turbulent flow (in particular, its internal structures)? Also, under what conditions do smooth solution to the Navier-Stokes equations exist?
Glass is a very general state of condensed matter  a large variety of systems can be transformed from liquid to glass
The liquid-glass transition cannot be described in the framework of classical phase transitions since Tg depends on the quenching rate  one cannot define an order parameter showing a critical behaviour at Tg

33. Why Disordered Systems ?
Convection of liquid metals creates the Earth's magnetic field. It deflects the solar wind. Without this field, the solar wind would directly strike the Earth's atmosphere. This would strip the Earth's atmosphere away slowly. This is hypothesized to have happened to the Martian atmosphere, rendering the planet incapable of supporting life.

34. Why at the nanoscale ?
The nature of the vibrational dynamics in glasses at the nanoscale is still unclear (V-SiO2)
P. Benassi et al., PRL 77, 3835 (1996)  Existence of propagating excitations at high frequency
M. Foret et al., PRL 77, 3831 (1996)  They are localized above ~ 1 nm-1
F. Sette et al., Science 280, 1550 (1998)  They are acoustic-like
G. Ruocco et al., PRL 83, 5583 (1999)  Change of sound attenuation mechanism at nm-1
B. Ruffle´ et al., PRL 90, (2003)  Change is at 1 nm-1
C. Masciovecchio et al., PRL 97, (2006)  Change is at 0.2 nm-1
W. Schirmacher et al., PRL 98, (2007)  Model agrees with Masciovecchio et al.
B. Ruffle´ et al., PRL 100, (2008)  Shirmacher model is not correct
G. Baldi et al., PRL 104, (2010)  Change is at 1 nm-1
PRL 112, (2014); Nat. Comm. 5, 3939 (2014); PRL 112, (2014)
Fundamental to understand the low temperature anomalies in glasses

35. Pressure (bar) Temperature (K) Pressure (bar) Temperature (K)
Why at the nanoscale ?
Water exhibits very
unusual
properties: -
Negative
volume of melting
- Density
maximum
in the normal liquid range
- Isothermal compressibility
minimum
in the liquid
- Increasing liquid
fluidity
with increasing pressure
“...water’s puzzling properties are not understood and 63 anomalies that distinguish water from other liquids remain unsolved....” H. E. Stanley, Physica A (2007)
Pressure (bar)
Temperature (K)
Pressure (bar)
Temperature (K) Tg TH TM
Ultrafast X-ray probing of water structure below the homogeneous ice nucleation temperature
The hope now is that these observations and our detailed structural data will help identify those theories that best describe and explain the behaviour of water.
J. A. Sellberg et al., Nature (2014)
HDA
HDL
CP2?
P. H. Poole et al., Nature (1992)
Liquid–Liquid Phase Transition
220 K – 100 MPa
Liquid
The liquid will experience spatial fluctuation characteristic of the LDL and HDL phases even though the liquid has not yet phase-separated
LDA
LDL r c
Solid

36. Why at the nanoscale ? WATER
……only by treating water as a viscoelastic system is it possible to understand the microscopic origin of water anomalies. The proposed scenario here has been developed using a dynamic approach……
F. Mallamace et al., PNAS (2013)

37. Solution: Free Electron Laser based Transient Grating Spectroscopy
TIMER w
(meV) -4 10 -3 -2 -1 1 2 V
= 500 m/s
= 7000 m/s
BLS
INS
Q ( nm )
IXS
IUVS
Solution: Free Electron Laser based Transient Grating Spectroscopy
Eprobe
Esignal
Epump
Q(l,q) q
F(Q,t)
S(Q,w) (a.u.)
w (meV)
H2O
2 nm-1
F(Q,t) (a.u.)
t (ps)
Gaussian-like time profile

38. Typical Infrared/Visible Set-UpM 1
Probe laser beam
Delay Line DM
2=21
Excitation laser beam
Phase Control (Heterodyne)
Beam stop (Homodyne)
Neutral Filter (Heterodyne)
Eex1 EL
APD M
Epr
Sample
DOE: Phase Mask
Eex2
AL1
AL2
Es (Homodyne)
EL+Es (Heterodyne)
Challenge: Extend and modify the set-up for UV Transient Grating Experiments

39. FEL pulse:1st and 3rd harmonic (λ3 = λ 1/3)
TIMER Layout 2θ θB
3rd harmonic (probe)
Delay line: 4 ML mirrors (abs 1st, reflect 3rd harm), time delays up to ~ 3 ns
“Original beam”
Vertical
Probe
Pump1
Pump2
Horizontal
Beam waist
FEL pulse:1st and 3rd harmonic (λ3 = λ 1/3)
1st harmonic (pump)
@ sample position
Vertical
Horizontal
Plane Mirrors
“beam splitters”
Focusing mirror
R. Cucini et al et al., NIMA (2011)

40. FEL Transient Grating Experiments on V-SiO2
λopt
Detector (EUV-Vis cross-corr.) θB
Beamstops
FEL2
Si3N4
reference
sample
FEL1
- FEL2
- FEL1
ΔtFEL-FEL= ± 0.5 ps at 2θ = constant M0
F. Bencivenga et al., NIMA (2010)
R. Cucini et al., NIMA (2011)
R. Cucini et al., Opt. Lett. (2011)
F. Casolari et al., Appl. Phys. (2014)
M. Danailov et al. Opt. Express (2014)
R. Cucini et al., Opt. Lett. (2014) M1 2θ M2

41. FEL Transient Grating Experiments on V-SiO2
F. Bencivenga et al., Nature 2015 M0 M1 M2 2θ θ
kFEL,1
kFEL,2 θB
lFEL = 27.6 nm
λopt
kopt
CCD
kfout
Permanent Grating after 1k-shots
Optical path difference < λFEL

42. Transient Grating Experiments on V-SiO2
Hyper - Raman modes due to
coupled tetrahedral rotations
Raman modes due to
tetrahedral bending
Acoustic-like excitations

43. Heterodyning with FEL
Heterodyning is a signal processing technique invented in 1901 by R. Fessenden
Time independent local field
I [arb. units]
λopt
kopt
CCD
kfout

44. Four Wave Mixing at FEL’s
w2 k2
w1 k1
w3 k3
w4 k4
Four Wave Mixing techniques are: Stimulated Raman Gain Spectroscopy, Photon Echo and Raman Induced Kerr Effect Spectroscopy, Femtosecond Stimulated Raman Scattering and Coherent Antistokes Raman Scattering (CARS) ω1 ω2 ω3
ωout VB CB
atom-A
atom-B Δt
Charge transfer dynamics in metal complexes
Charge injection and transport in metal oxides nanoparticles
Charge Density Wave (Commensurate and Incommensurate)
Quasiparticle diffusion (Polarons)
Measure the coherence between the two different sites  tuning energies and time delay makes possible to chose where a given excitation is created, as well as where and when it is probed
delocalization of electronic states and charge/energy transfer processes.
S. Tanaka and S. Mukamel, PRL (2002)

45. Θpump
Θprobe t
l1pump l2
Ti grating

46. Element selective magnetization dynamics
E. Ferrari et al., (2016)
Radiators at different harmonics DT
Ni0.81Fe0.19
NiFe2O4

47. Pump & Probe on Silicon Pump FEL Probe FEL
E. Principi et al., in preparation
P. F. McMillan et al., Nature (2005)

48. DT FERMI based CARS THG 𝝀seed  261.7 nm OPA 𝝀seed variable
𝝀2  𝝀1 - 𝝀
𝝀1  nm
THG 𝝀seed  nm
OPA 𝝀seed variable
2 colored
FEL Pulses
F. Bencivenga et al., in preparation

49. FERMI based CARS Si3N4 Si3N4 Diamond
TG signal (phot/shot)
Δt (ps)
Si3N4
Si3N4
CARS signal (phot/shot)
Δt (ps)
CARS signal (a.u.; log)
Δt (ps)
Diamond
ωEUV1-ωEUV2=165 meV
A factor 50 less in the count rate
The signal seems to drop faster
TG signal extends over 100’s ps
CARS one is “undetectable” above few ps
F. Bencivenga et al., in preparation

50. Photocorrelation @ FERMI
Dynamic Sample
Advantages
NO needs for a monochromator  coherent lenght ~ 103 l (nm)
(factor 102)
NO delay line: use two different electron bunches with a radiofrequency cicle temporal distance (minimum step Dt ~ 330 ps, maximum delay 10 ns) ~

51. Absorption lenght: 103mm @ X-ray (factor 102)
PCS on Water
Absorption lenght: – 10 nm
Absorption lenght: X-ray (factor 102)
wavelenght
Refractive index
J.A. Sellberg et al., Nature (2014)
Study of
Water Thermo-Dynamics
Spinodal decompositions
Disordered Systems relaxatons
Collaboration with A. Nilsson group

52. Optical TG in FM thin films one-to-one correspondence
Optical TG used for probing
magneto-elastic waves in Ni
J.Janusonis et al., APL (2015)
Faraday and TG exhibits the same dispersion
one-to-one correspondence
between acoustic and magnetic response

53. Sub-Optical TG in FM thin films
λopt (~ nm)
Faraday Rotation Detection
Study of
Magneto – Acoustic coupling
Q – dependence of Magnetic Waves
Excite with FEL short l and probe with Faraday detector to see the acoustic waves

54. Conclusions Charge transfer dynamics in metal complexes
M. Chergui
K. Nelson
T. Scopigno
Charge transfer dynamics in metal complexes
Charge injection and transport in metal oxides nanoparticles
Vibrational modes in Glasses
Charge Density Wave
Quasiparticle diffusion (Polarons)
Sound velocity in Graphene
G. Knopp
S. Mukamel
G. Monaco 54

55. Advertisement Jerry Hastings (SLAC) Shaul Mukamel (UCI)
Thomas Tschentscher (XFEL) Anders Nilsson (SLAC)
Andrea Cavalleri (MPSD, CFEL) Philippe Wernet (HZB)
Chergui Majed (EPFL) Ulf Zastrau (XFEL)
Villy Sundstrom (University of Lund) Ryan Coffee (SLAC)
Emma Springate (Central Laser Facility, STFC) Arnaud Rouzée (MBI)
Alfred Leitenstorfer (University of Konstantz) Filippo Bencivenga (Elettra)
Oliver Gessner (LBNL) Maurizio Sacchi (CNRS Paris)
Jos Oomens (University of Radboud) Kevin Prince (Elettra)
Ian Robinson (London centre for Nanotechnology) Thomas Pfeifer (MPI)

56. Acknowledgments C. Callegari L. Giannessi M. Danailov M. Zangrando
F. Parmigiani
M. Kiskinova
A. Battistoni
F. Capotondi
M. Di Fraia
P. Finetti
M. Manfredda
E. Pedersoli
R. Cucini
O. Plekan
A. Gessini
R. Richter
M. Coreno
E. Giangrisostomi
E. Principi
F. Bencivenga
K. Prince
R. Mincigrucci