[PPT] - Recent Developments at the Brookhaven Source Development Laboratory PowerPoint Presentation

SLIDE 1

Recent Developments at the Brookhaven Source Development Laboratory

Brian Sheehy National Synchrotron Light Source Brookhaven National Laboratory Beam Physics Seminar Jefferson Laboratory

October 15, 2004

SLIDE 2

The SDL Team

G. L. Carr, E. D. Johnson, S. Krinsky, H. Loos , J. B. Murphy, J. Rose, T. Shaftan, B.

Sheehy, Y. Shen, X.-J. Wang, Z. Wu, L. H. Yu National Synchrotron Light Source; Brookhaven National Laboratory

Facility Overview
Diagnostics/Control
High Gain Harmonic Generation (HGHG)
Cascading
Tunability
Optical Compression and and Shaping coherent FEL output
SPIDER and CPA
Other Sources
MV/cm peak field THz source

SLIDE 3

Facility Overview

Adjustable Chicane 177 MeV RF zeroPhasing Photoinjector CTR Monitor Normal incidence 77 MeV FEL seed at 800 nm Modulator Undulator NISUS pop-in monitors FEL Measurement Energy, Spectrum, Synchronization and Pulse Length Measurements at 266 nm s Ion Pair Imaging Experiment at 88 nm Nisus Wiggler 30 mJ Ti:Sapphire Amplifier Dispersion Magnet Trim Chicane

BNL Gun IV photoinjector, S-band, 4.5 MeV
4 stage Linac up to 200 MeV
upgrade to 250-300 MeV near completion
Magnetic Chicane Compressor R56 = 5 cm
Seed at λs= 800 nm in 1 m undulator K=1.67 , followed by dispersive section
NISUS undulator, 10 m, 256 period, K = 1.1
fundamental at λs /3 = 266 nm, output 100 µJ
1 µJ at third harmonic λs /9 = 89 nm

SLIDE 4

Diagnostics/Control

Unmatched Unmatched

200 400

RMS size (um)

εn 4.78 ± 0.42 µm β 3.73 ± 0.38 m α -0.95 ± 0.09 horizontal 2 4 6 8 10 200 εn 4.12 ± 0.10 µ m β 4.03 ± 0.15 m α 0.51 ± 0.04 vertical 100 200 300 εn 4.00 ± 0.19 µ m β 3.26 ± 0.20 m α 0.09 ± 0.07 2 4 6 8 10 100 200 εn 4.23 ± 0.15 µ m β 3.16 ± 0.16 m α 0.28 ± 0.05

Transverse beam parameters Transverse beam parameters

400 400

Distance (m)

Matched Matched Automated beam matching in NISUS

over 30 Ce:YAG pop-in beam

position monitors (BPM), including 17 in the radiator

Automated beam matching and

emittance measurements

Optical
longitudinal electron beam

tomography

CSR instability question
temporal beam shaping
electro-optic electron beam

measurements

SLIDE 5

Diagnostics/Control

10
8
6
4
2

2

40
30
20
10

10 20 30 40 0.5 1 1.5 2

Time (ps) Phase matching angle (mrad) Signal 100 fs IR 5 ps UV BBO crystal 250 fs blue Power meter

BBO Crystal Detector Reference Detector Micrometer delay stage Wedged beam splitter 266 nm HGHG light

Layout of the two-photon absorption pump-probe autocorrelator

Photocathode Drive Laser: 250 fsec resolution cross – correlation with

scillator
shaping: emittance, THz
two photon absorption autocorrelator for

266 nm output

picosecond resolution synchroscan

streak camera

visible & XUV monochromators
SPIDER: complete field measurement
f FEL output

SLIDE 6

RF Zero Phase RF Zero Phase

100 150 200 250 300 40 60 80 100 120 140 100 150 200 250 300 350 40 60 80 100 120 140 160 180 50 100 150 200 250 300 350 400 20 40 60 80 100 120 140 160 180 200

Uncompressed beam on pop14 Mild compression Strong compression.

Head Tail Head Tail Head Tail

Positive RF slope Accelerate bunch at RF zero-crossing Image at screen depends on energy spread Bending magnet generates dispersion Zero RF slope Negative RF slope

Yikes! CSR Instability?

Use linac phase to ‘streak’ the bunch on screen

But!

This is really an energy measurement, not a current measurement

SLIDE 7

Longitudinal phase space tomography (H. Loos)

400

400

400

400

400

400

400

400

400

400

400

400

400

400

400

400

400

400

400

400

400

400

400

400

400

400

400

400

400

400

400

400

Spread (keV)

4
2

2 4

20
10

10 20 Time (ps) Energy (keV)

6
4
2

2 4 6

10

10 ∆E (keV)

6
4
2

2 4 6 25 50 Current (A)

6
4
2

2 4 6 0.1 0.2 0.3 Time (ps) Intensity

t E

Drive laser current E-t corr

Each value of the chirp manifests a different projection of the phase space.

SLIDE 8

The energy projection can be very deceptive

Huang & Shaftan NIMA 528, 345 (2004)

Current and energy profiles of a chirped beam (a) without energy modulation, (b) with energy modulation.

SLIDE 9

Degree of modulation observed inconsistent with CSR models
S. Heifets, G. Stupakov and S. Krinsky PRST-AB 5, 064401 (2002)
Z. Huang & H.-J.Kim PRST-AB 5, 074401 (2002)
Z. Huang T. Shaftan SLAC-PUB-9788, 329.
Longitudinal Space Charge model:
small modulation in photocathode drive laser
small current modulations due to drive laser modulations at photocathode
longitudinal space charge forces result in enhanced energy modulations in the

bunch

these dominate the horizontal distribution in zero-phase measurements
experimental confirmation
lack of coherent enhancement of the IR in coherent transition radiation
modulation behavior with chicane strength, trans beam size, energy, etc
phase space tomography

potential threat for short pulse short wavelength FEL’s

can convert to current modulation; larger energy spresd
goes away for perfectly uniform laser temporal profile

Theory: Huang & Shaftan NIM A 528, 345 (2004) Experiment: Shaftan et al NIM A 528, 397 (2004)

SLIDE 10

Ti:Sapph Oscillator Dazzler Stretcher Amplifier Compressor ω−tripler

800 nm 9 nJ 100 fsec 5 nJ 200-400 psec 25 mJ 170-350 psec 15 mJ 0.1 - 30 psec 266 nm 1.8 mJ Time (psec) Intensity (arb units)

Temporal Shaping (in progress)

At SDL in collaboration with SPARC and SLAC Amplified and compressed IR pulse

SLIDE 11

Millennia Laser Tsunami Laser

S p e c t r u m A n a l y z e r

A u t

c
r

r e l a t

r

Optical Isolator Stretcher Compressor 1 Regenerative Amplifier

2-pass Amplifier 2-pass Amplifier

Variable Power Divider

P h

t
c

a t h

d

e G C R

1

7 Y A G L a s e r G C R

1

5 Y A G L a s e r

Photodiode

P

w

e r A t t e n ω + ω = 2 ω ω + 2 ω = 3 ω

Autocor- rellator Spot Imaging Power Mon Optical Relay, 14 meters Monument Power Atten Spatial Filter Compressor 2 Optical Relay, ~35 meters Seeding And Diagnostics

Dazzler

SLIDE 12

ZnTe Accelerator Trim Modulator Dipole Monitor Polarizer Analyzer λ/4 Plate to NISUS Spectro- meter Fiber Trim Seed Laser Delay

Electrons Laser

(800 nm)

Electro-Optic e-beam meaurements ( ) λ

ε π ϕ + = ∆ 1 2

vac 41 3

l E r n

Retardation induced by e-bunch field Evac

R T R T + − = ∆ ) sin( ϕ

Asymmetry in transmitted/reflected gives ∆ϕ Chirp seed and spectrally resolve the asymmetry – single shot measurement (800 fsec resolution). Jitter 150 fsec rms over 20 seconds

r chirp

SLIDE 13

High Gain Harmonic Generation (HGHG)

e-

Self amplified Spontaneous Emission (SASE)

Spontaneous emission microbunching enhanced emission

Noisy
Broad Bandwidth
Not longitudinally coherent
HGHG

Seed modulates e- energy coherent microbunching emission

Short wavelength : tune radiator to harmonic of seed
Stable
Narrow bandwidth, higher brightness
Longitudinal coherence

Spectrum

1 2 3 1 2 3 p(E)

σ= 41%

E/<E> 1 2 3 5 10 p(E)

σ = 7% Energy Fluctuations SASE HGHG

SLIDE 14

Cascading HGHG to soft X-ray wavelengths (L.H Yu)

1-ST STAGE 2-ND STAGE 3-RD STAGE FINAL AMPLIFIER

AMPLIFIER

λw = 6.5 cm

Length = 6 m Lg = 1.3 m AMPLIFIER

λw = 4.2 cm

Length = 8 m Lg = 1.4 m AMPLIFIER

λw = 2.8 cm

Length = 4 m Lg = 1.75 m MODULATOR

λw = 11 cm

Length = 2 m Lg = 1.6 m MODULATOR

λw = 6.5 cm

Length = 2 m Lg = 1.3 m MODULATOR

λw = 4.2 cm

Length = 2 m Lg = 1.4 m DISPERSION

dψ/dγ = 1

DISPERSION

dψ/dγ = 1

DISPERSION

dψ/dγ = 0.5

DELAY DELAY DELAY “Spent” electrons “Fresh” electrons “Spent” electrons

“FRESH BUNCH” CONCEPT

“Fresh” electrons

e- e-

266 nm SEED LASER 53.2 nm 2.128 nm 10.64 nm ÷5 ÷5 ÷5 400 MW 800 MW 70 MW

1.7 GW

500 MW

e- e-

LASER PULSE AMPLIFIER

λw = 2.8 cm

Length = 12 m Lg = 1.75 m

e-beam 750Amp 1mm-mrad 2.6GeV σγ /γ=2×10 – 4

total Lw =36m

SLIDE 15

A proposed 2 stage cascade for the SDL e-beam 600Amp 250 MeV 2.7 mm-mrad σγ / γ = 1.×10 - 4 Pin=1.5 MW 266nm 66.5 nm Pout=140 MW 56 MW 133nm

2m VISA 6 m NISUS 0.8m MINI

Pulse length ~ 0.5ps 70µJ

SLIDE 16

A Novel Tunability scheme for HGHG (T. Shaftan) Radiator DS Modulator

1 1 174.5 175 175.5

.

1 1 174.5 175 175.5

.

1 1 174.5 175 175.5

.

Seed with fixed λ

before FEL after Modulator after DS

E [MeV] E [MeV] E [MeV]

t [ps]

Dispersive Section (DS) converts energy modulation into bunching
DS also compresses the energy modulation wavelength
a small but measureable effect in our machine, but could be optimized to

yield a tuning range of 20%

(Dispersive Section)

SLIDE 17

Optimal tunability configuration Klystron Radiator DS Modulator XRF XRF

1 1 1 1

.

1 1 1 1

.

1 1 1 1

.

1 1 1 1

.

1 1 1 1

.

time HGHG

Seed with fixed λ

energy

Compression or stretching in the dispersive section can be used to modify the period of the microbunching. This is ordinarily a small effect, but it could be

ptimized to yield ~20% tunability.

SLIDE 18

SDL Experiment

Chirp is provided by shifting beam off-crest in tank 4

(Emax = 58 MeV)

Tank 4 phase shift: from +25° to -45°
DS is set to maximum current (200 A)
Nothing else was changed !
Spectrum of HGHG is measured

for different amounts of chirp

Gun 4.5 MeV Tank 1 Tank 2 Tank 3 Tank 4 35 MeV 72 MeV 130 MeV 190 MeV

Mod DS NISUS 266 nm

0.8 um

.

Tank 4 phase Tank 4 energy gain

seed

SLIDE 19

HGHG output spectra for various tank 4 phases:

45°
30°
10°

0° +10° +25° Wavelength, nm HGHG intensity, a.u.

SLIDE 20

Fit, based on R56(DS)=0.34 mm

0.8 0.6 0.4 0.2 0.2 0.4 0.6 263 264 265 266 Wavelength versus chirp

sin(phi4) Wavelength [nm]

263.28 265.92 0.3 0.2 0.1 0.1 0.2 0.3 263 264 265 266 Wavelength versus energy

Energy detuning, % Wavelength [nm]

∆λ/λ≈1 % FEL ρ Fit including R56

f DS and radiator

Additional compression in the radiator

SLIDE 21

Spectral Phase Measurements; chirping and shaping FEL output

Optical Compression and and Shaping coherent FEL output
Measuring Spectral Phase
SPIDER technique
Application at 266nm for picosecond laser pulses
Measurements HGHG
Unchirped, narrow bandwidth
Near transform limit
Chirping and Compressing

SLIDE 22

High Gain Harmonic Generation (HGHG) and Chirped Pulse Amplification (CPA)

time frequency time e- energy time frequency

ω e- e-

Optical compressor time frequency

Tb T<<Tb

Match optical seed chirp to electron energy chirp
Resonant frequency in modulator matches

seed at each moment in the bunch

Output pulse is also chirped
Longitudinal coherence permits optical

compression to transform limit

femtosecond pulses
Sensitive to spectral phase distortion
Li Hua Yu et al Phys Rev E 49, 4480 (1994)

SLIDE 23

Shaping HGHG

Coherent control at short wavelengths
For both chirping and shaping, the question is:

How will phase modulation in the seed transfer to HGHG?

Can distortions be used as a probe of e- beam and radiator dynamics

Potential Problems / Interesting Questions

synchronization jitter
stability
noise & harmonics
optical field is bipolar, electron density is not.

SLIDE 24

(Walmsley group, Oxford)

266 nm 400 nm

800 nm

Measuring the spectral phase: SPIDER (Spectral Interferometry for Direct Electric-Field Reconstruction) ωc D(ωc)

2π/τ

C. Iaconis and I. A.

Walmsley, Opt. Lett. 23, 792–794 (1998).

SLIDE 25

DOWNCONVERSION SPIDER LAYOUT

Spectrometer 800 nm (seed) + 266 nm (HGHG) Michelson interferometer BBO

.

266 nm 800 nm Filter Compressor used as stretcher Delay Line 400 nm

Separate seed pulse (800 nm) and HGHG
stretch seed to 60 psec
make 2 HGHG pulse replicas in

interferometer and separate by τ=3.5 psec

Downconvert to 400 nm in BBO
frequency shift is Ω=0.2 THz
set spectrometer to λc=800 nm
measure 400 nm SPIDER trace

in 2nd order

block seed, remove filter and

measure 266 nm calibration trace in 3rd order

SLIDE 26

ang

SLIDE 27

Spidering a laboratory 266 nm source

0.05

0.05

10

10 20 30 ω - ω0 (PHz) radians amplitude phase fit chirp phase-chirp

0.05

0.05 0.2 0.4 0.6 0.8 1 ω - ω0 (PHz) intensity (arb units)

Typical Spider Trace Reconstructed phase and amplitude Comparison with x-correlation

stretch a 100 femtosecond 800 nm Ti:Sapph

chirped-pulse-amplification system

Frequency-triple in BBO to 266 nm(spoil phase

matching to create an asymmetry in the time profile)

Compare scanning multishot cross-correlation
f the 266 nm and a short 800 nm pulse with the

average reconstruction, convolved with 250 fsec resolution of the x-correlator

1
0.5

0.5 1 1.5 0.2 0.4 0.6 0.8 1 time (psec) intensity (arb units) spider cross correlation

900 fsec FWHM

SLIDE 28

UNCHIRPED HGHG

time frequency time e- energy time frequency

Tb

ω e- e-

Stretch seed to 6 psec
optimize compression / minimize e- energy chirp
minimize output bandwidth

SLIDE 29

Frequency vs time

UNCHIRPED HGHG * 3

Spectral Phase

flat phase across the pulse
residual seed chirp not visible
frequency vs time constant

Temporal Phase

SLIDE 30

50 shots

5 10 15 2 4 6 8 10 12

rms spectral width σ (THz) number of shots

0.2 0.4 0.6 0.8 5 10 15 20

rms temporal width σ (psec) number of shots

σω=5.5 0.7 THz στ=0.20 0.01 psec

Define transform

limit as the pulse when spectral phases are set to zero.

pulses are 1.4 0.1

times transform limit

width tran ltd width

σωστ = 1.1, twice transform limit

for a Gaussian pulse

FWHM = 440 80 fsec
pulses are not Gaussian

207 fs rms 168 fs rms

UNCHIRPED HGHG

SLIDE 31

time frequency time e- energy time frequency

Tb

ω e- e-

CHIRPED HGHG

Chirp e- bunch and optical seed together
optical seed: 3.8 THz/psec
e- bunch: 2.7 THz/psec (resonant frequency)
broader bandwidth already observed

Doyuran et al PRST AB 7, 050701 (2004)

SLIDE 32

CHIRPED HGHG

* 3

SLIDE 33

CHIRPED HGHG

* 3

SLIDE 34

CHIRPED HGHG

* 3

SLIDE 35

CHIRPED HGHG

* 3

SLIDE 36

Time (psec) Frequency (THz)

Distribution of chirps fit over a 200 fs window around peak center CHIRPED HGHG

seed chirp * 3

Sources of instability
optical chirp / e- chirp mismatch
synchronization (150 fsec rms)
compression instability
rf curvature
The seed chirp is clearly observed

in the HGHG output over part of the pulse

distortion in the pulse wings

deteriorates compressibility

SLIDE 37

Matching Electron and Optical Chirp λ t γ Optical Beam Electron Beam

Electron beam has curvature due to sinusoidal acclerating field
If chirp is not matched, resonance occurs only over a short portion of

the electron bunch – correlation between compressibility and uncompressed pulse length?

Mismatched is more sensitive to synchronization jitter.

SLIDE 38

Uncompressed rms pulse width (fsec) Compression Factor

correlation between compressibility and uncompressed pulse length

SLIDE 39

Compression factor rms width ‘compressed’ width ‘compressed width/transform limit

most pulses compressible in principle to ~ twice

transform limit

quadratic spectral phase (defines compressor) not

determined only by chirp

a ‘reasonable’ fixed compressor compresses only

15% of pulses

Fit b for each shot and ‘compress’:

SLIDE 40

CPA Summary

Successfully demonstrated SPIDER at shortest wavelength

and longest pulse lengths reported.

Characterized spectral phase of High Gain Harmonic

Generation

near transform limited
Chirped Pulse Amplification
Imparted positive chirp commensurate with seed chirp
poorly matched electron chirp
sensitivity to other factors still unclear
shown the viability of CPA and potential for more complex

pulse shaping

SLIDE 41

GaAs

Typical Laser-based THz Source UF laser THz

Transient current is subpicosecond, Ea ~ 10 kV/cm
Relaxation is slow: half-cycle pulse
THz yields: 1 nJ (250 kHz) to 1 uJ (1 kHz),
size scaling limit 1 - 10 uJ
optical rectification yields are similar w/ higher freqs.

photocathode electron gun dipole chicane compressor

~ 300 fs, 700pC electron bunches

(can be shorter w/ less charge) Coherent THz transition radiation

Note: <10 Hz rep. rate

Coherent THz dipole radiation

SDL LINAC-based THz Source

bunch length ~ λ, coherent enhancement
energy of 80 uJ measured in this setup ( E ~ 1 MV/cm)
2 orders of magnitude larger than other sources
Scales as Ne-

2

spectral content to 2 THz
higher for shorter bunches
This machine is not optimized for THz production

2 Intensity Frequency (THz)

SLIDE 42

Coherent Transition Radiation

Transition radiation occurs when an electron crosses the boundary between two different media. For a relativistic electron (β ≡ v/c ≅ 1) incident on a perfect conductor, the number of photons emitted per solid angle and wavelength range is:

( )

θ β θ θ β λ π α λ

2 2 2 2 2 2

cos 1 cos sin − = Ω d d dN

Intensity is 0 on axis, peaks at θ ~ 1/γ.

Polarization is radial

Coherent radiation emission:

50
25

25 50

Intensity (rel.) Angle (mrad)

Far field distribution for γ = 200

dWN /dω = N2 dW1 /dω | f (ω)|2

( ) ( )

2 / ˆ

∫

∞ ∞ − ⋅

= dr r S e f

c r n i

ω

ω

where (Nodvick & Saxon)

SLIDE 43

Electro-Optic measurement of THz field

Polarization of synchronized optical field is retarded by

instantaneous THz field in the ZnTe crystal by Pockels effect

analyzer gives time resolved 2-dimensional distribution of

electric field component

C C D ZnTe Analyzer Polarizer Lens Electron Beam Vacuum Window Paraboloid Coupling Hole, 2 mm Ti:Sa Laser Delay

λ/4

EO Detection method:

T.F. Heinz/Columbia & X.-C. Zhang/Rensselaer

Accelerators:

Yan, Van der Meer et al PRL 2000 Wilke et al PRL 2002 Loos et al PAC 2003

Chirped sampling:

Jiang and Zhang, APL (1998)

SLIDE 44

Pixels Pixels 100 200 300 400 500 600 100 200 300 400 Horizontal (mm) Vertical (mm)

2
1

1 2

2
1

1 2

Image Processing for electric field recovery

Use compensator waveplate to detect sign of polarization change.
Reference IR (left) and Signal IS (right) obtained simultaneously.
Rescale and normalize both.
Calculate asymmetry A of Signal.
Subtract asymmetry pattern w/o THz.

A = 2IS/IR - 1

SLIDE 45

Coherent THz Transition Radiation Pulses from the SDL Linac

0.0 0.5 1.0 20 40 60 80

Pyroelectric Detector Response [µJ] Time [ms]

Up to 80 µJ (!) per pulse

> consistent with

calculation

20 40 60 2 4 6 8 10

Intensity [arb.] Frequency [cm

1]

1 2

Frequency [THz]

Intensity to 2 THz (higher with shorter bunches) photocathode electron gun dipole chicane compressor

~ 300 fs, 700pC electron bunches

(can be shorter w/ less charge) Coherent THz transition radiation

Note: <10 Hz rep. rate

Coherent THz dipole radiation

SLIDE 46

THz beam path and analyzer

SLIDE 47

Beam Paths in Analyzer OAP OAP ZnTe ZnTe BS BS λ/4 λ/4 Pol. Pol. R e f R e f S i g n a l S i g n a l Camera Camera

SLIDE 48

CTR simulation (H. Loos)

30 mm

Decompose electron

beam coulomb field in Gauss-Laguerre modes.

Calculate complex

transmission factors through experiment for THz spectral range.

Use bunch form factor

to reconstruct time dependence.

20 ps

SLIDE 49

Cross section of E-field at focus as a function of time

E-field along horizontal plane

Note: opposite sides are asymmetric, as shown (radial polarization)

Measurement Calculation

(mm)

Temporal-spatial E-field profile of coherent transition radiation pulse at ~ f/1.5 focus

SLIDE 50

Opportunities in Magnetism for THz pulses

(Epeak = 1 MV/cm → Bpeak = 3 kilogauss)

m a g n e t i c v i s c

s

i t y field (gauss)

Ultra-Short Pulses and/or High Fields -- D. Arena / NSLS

Current state of the art for “ultra-fast” dynamics experiments:

10-15 10-12 10-9 10-6

Excitation / I nteraction

e x c h a n g e i n t e r a c t i

n

S t

n

e r e x c i t a t i

n

s s p i n w a v e s ( l

w

q l i m i t ) s p i n

l

a t t i c e r e l a x a t i

n

i n m a n g a n i t e s p r e c e s s i

n

a l r

t

a t i

n

a n d d a m p i n g s p i n c

h

e r e n c e a n d s p i n d i f f u s i

n

Coercivity / Saturation

time (sec)

105 104 101 102 103

soft manganites permalloy transition metals & alloys a″ Fe16N2 dilute magnetic semicond. rare-earth magnets

Role for THz!

Time: ~100 fs (lasers) ~100 ps (synchrotron) Field: ~10 – 100 gauss (stripline)

SLIDE 51

Soft Modes in Ferroelectrics & Perovskites (PbTiO3)

G. L. Carr

Use half-cycle pulse to coherently drive atoms, probe motion as a function of time (needs diffraction probe).

THz HCP

E

THz HCP

E

THz HCP

E

E(t)

Observe “shift” in diffraction spot(s)

DOE Workshop on Ultrafast X-rays

SLIDE 52

Why Make Terahertz Pulses ?

Imaging/Remote Ranging

– non-ionizing – medical – safely use to monitor public or battlefield environments – CHEMICALLY AND BIOLOGICALLY SENSITIVE – explosives, weapons detection – phonon modes in DNA (Woolard et al Phys Rev E 65, 051903) – remote ranging with bacterial species identification – a lot of work remains in sources, detection, and characterization. explosives weapons

Woolard et al THz Differential Absorption Radar model (Bio early warning) 1 km

SLIDE 53

Some More Reasons

Ultra-fast dynamics (< 1 ps time scale)

– directly measure complex dielectric response of sample – strong coupling of optical/THz excitations in correlated e- systems (e.g. high- Tc superconductors)

Low frequency, non-linear properties of materials

– nanoparticles / quantum dot arrays in dielectrics – Optronics: Ultrafast components in all-optical circuits – faster, EMP resistant

Orienting Molecules

– spectroscopy and chemistry from coherent rovibrational states – manipulate internal molecular fields / fundamental measurements & coherent control

Structural transitions

–Large E-field to coherently “shove” atoms

SLIDE 54

THz Summary

The DUVFEL THz source pulse energy exceeds other sources by 2 orders of

magnitude (DUVFEL 80 uJ, Laser sources 1 uJ, JLab ERL 0.5 uJ)

fundamental dynamics ( magnetic systems, strongly correlated e- systems,

nanoparticles…)

large area imaging
single shot detection
explore nonlinear effects
THz as pump in pump-probe experiments
MV/cm E-fields and kilogauss B-fields
THz pulse shaping (through e-beam and optically)
Accelerator sources have not been optimized for THz production

SLIDE 55

Global Summary SDL continues to be an important test bed for FEL science and technology development, as well as a user facility

answers to important questions of beam dynamics for

next generation sources HGHG is an extremely promising candidate for producing longitudinally coherent short wavelength ultrafast pulses

tunability
chirped pulse amplification and Shaping
cascading is in the works

The THz production is a truly unique source capable of

pening a new regime of dynamics to study