Linear and Pump-Probe applications of THz Spectroscopy: The case of Elettra, Bessy-II, and SPARC

Linear and Pump-Probe applications of THz Spectroscopy: The case of

Elettra, Bessy-II, and SPARCS. Lupi

Dipartimento di Fisica, INFN-University of Rome La Sapienza, and SISSI@ELETTRA, Italy

SISSI

Synchrotron Infrared Source for Spectroscopy and Imaging

Outline

• THz Radiation production from III Generation Machines: the case of Bessy-II and Elettra;

• THz Linear Spectroscopy: Applications in Superconductivity and Strongly Correlated Materials;

• Pump-Probe THz Experiments in Superconductivity and Strongly Correlated Materials;

• High-Power/Sub-ps THz Pulses @SPARC;

Outline





THz Coherent radiation production from III Generation Machines: Bessy-II and Elettra

€

Itot (ω) = Isp (ω)[N +N(N −1)F(ω)]

F(ω) = dzS(z)eiωcz∫Emission in the FIR/THz range is drastically enhanced.

Bessy-IIIRIS Beamline

U. Schade et al, PRL 2003

A. Perucchi et al,IP&T 2007

ELETTRASISSI Beamline

€

σz ≈ E 3 / 2

CSR

Gl

Take Home Message

III Generation MachinesHigh Rep Rate: 500 MHzLow-Energy per pulse: pJSeveral ps bunch length

Needed to compress the bunchSpecial Operation Mode

Linear THz Spectroscopy

Outline





Superconductivity today:

THz spectroscopy plays a fundamental role

... because

Superconductivity is ruled by low-energy electrodynamics:

• Superconducting gap : THz range• Spectral weight of condensate and penetration depth: THz

• Mediators of pairing (phonons, etc.): THz• Range of sum rules: THz, Mid, or Near Infrared

• Free-carrier conductivity above Tc: Infrared

Basic optics of SuperconductorsSuperconducting gap observed if:-sample in the dirty-limit (2 < )

-Cooper pairs in s-wave symmetry

σ1

sup

( ω ) =

ω

2

ps

8

δ ( ω ) + σ1

reg

( ω )

∫ [σ, T>Tc) - σ, T<Tc)] d ps/8 = nse2/m*--> =c/ps

Ferrel-Glover-Tinkham Rule

40x103

30

20

10

0

σ

) Ω

−cm-1

)

200150100500

ω (cm-1)

Normal State T = 0.9 Tc T = 0.6 Tc T = 0

Superconducting Gap

1.000

0.995

0.990

0.985

0.980

Reflectance

100806040200 cm-)

Norma State T 0.9 Tc T 0.6 Tc T 0

Drude absorption

Drude reflectance

2

Minimum excitation energy:Cooper-pair breaking 2

Superconductivity in Boron doped Diamond

Oppenheimer Diamond 254.7 carats

Takenouchi-Kawarada-Takano Diamond 0.7 carats

86420

ZFC FC

-5

-10

0

m 0-4

e.m.u) m 0

-5

e.m.u)

00

-

-4

TK)

B-Diamond: a text book example of BCS superconductivity

s-wave Dirty-Limit Regime; 2(0)=12±1 cm-1 20)/kBTC=3.2 ± 0.5

1.05

1.00

3020100

1.00.80.60.40.20.0

T=2.6 K 3.4 K 4.6 K 7.2 K 15 K

8

6

4

2

01.00.50.0

cm-)

T / TC

THz)

Rσ

T) / R

n

5K)

cm -)

Mattis-Bardeen Model

≤ (T) : Rn () = 1 - [8(T)/ p2]1/2 ≤ 2(T) : Rs() = 1

Peak at 2 in Rs/Rn

M. Ortolani et al, PRL, 2006

1.00

0.95

0.90

0.85604020

cm -)

T.6K 3.4 4.6 7. 5

Mott-Hubbard Insulator to Metal Transitions

Filling-Controlled MIT:• static (doping)

Bandwidth-Controlled MIT:• static (pressure)

U Coulomb repulsiont Bandwidth

Mott-Hubbard Insulator to Metal Transition

E. Arcangeletti et al, PRL (2007)

VO2

Pressure (Bandwidth) controlled MIT

V2O3

Outline





Breaking Cooper Pairs DynamicallyPhotoionization

For hω>2Δ light breaks Cooper pairs1) Optical Pump - Optical Probe (THz Probe) hω>>2Δ Recombination Dynamics affected by excess phonons

2) THz Pump – THz Probe hωTHz≥2Δ Intrinsic dynamics

Alternative processes if hω<2Δ Δ=Δ(J, B) at fixed T<Tc

The high E (~MV) THz field may induce currents exceeding the critical current (breaking the Superconducting State with an Electric Field)

The high B (~1 T) THz field may be larger that Bc(breaking the Superconducting State with a magnetic Field)

THz controlled Mott-Hubbard MIT

THz pulses in the MV/cm range can drive lattice displacements

in the pm range

Filling-Controlled MIT:• static (Doping)•Dynamic (Phoexcitation)

Bandwidth-Controlled MIT:• static (Pressure)•dynamic (Radiation)

U Coulomb repulsiont Bandwidth

Dynamical modulation of U through intramolecular pumping

Outline





Acceleration section

Ondulator Section

THz Section

Laser

Free Electron Laser SPARC@INFNBeam energy 155–200 MeVBunch charge 1 nCRep. rate 10 HzPeak current 100 Aen 2 mm-mraden(slice) 1 mm-mradσ 0.2%Bunch length (FWHM) 10 ps-100 fs

Transition Radiation occurs when an electroncrosses the boundary between two different media

Intensity is 0 on axis and peaked at /Polarization is radial

CTR-THz Radiation

Velocity Bunching: Bunch length versus injection phase

If the beam injected in a long accelerating structure at the crossing field phase and it is slightly slower than the phase velocity of the RF wave , it will slip back to phases where the field is accelerating, but at the same time it will be chirped and compressed.

0.876 ps/mm

σt = 160 fs

Velocity Bunching

1.389 ps/mm

σt = 2.586 ps

Tim

e

CTR-THz emission

500 fs, 250 pC

300 fs, 500 pC

2 ps

E. Chiadroni et al., J.Phys. 2012E. Chiadroni et al. APL 2012 S Lupi et al ., J. Phys 2012M. Ferrario et al., NIM A 2011

CTR measured emission from LINACsElectron

beam energy

Charge t(bandwidth)

THz pulse energy

E-field

Brookhaven(1) 120 MeV ~ 1 nC -(2 THz)

≈100 mJ MV/cm

SPARC(2) 120 MeV 500 pC 120 fs(10 THz)

≈100 mJ MV/cm

FLASH(3) 1.2 GeV 600 pC -(4 THz)

>100 mJ MV/cm

LCLS(4) 14.5 GeV 350 pC 50 fs(40 THz)

140 mJ >20 MV/cm

(1) Y. Shen et al., Phys. Rev. Lett. 99, 043901 (2007)(2) E. Chiadroni, et al., APL 2012(3) M.C. Hoffmann et al., Optics Letters 36, 4473 (2011)

(4) D. Daranciang et al., Appl. Phys. Lett. 99, 141117 (2011)

Perspectives• Increase machine energyincrease of bunch-charge (1 nC);• Tailoring the electronic bunch shapeextended spectral coverage

(20 THz);• Narrow band THz radiationSmith-Purcell Radiation:

Narrow-band and Tunable THz Radiation

Acknowledgments

• A. Perucchi (SISSI@ELETTRA)• E. Karanzoulis (ELETTRA)• U. Schade (IRIS@BESSY-II)• E.Chiadroni and M. Ferrario (LFN-INFN):

TERASPARC project

Thank for your attention

Documents

Linear and Pump-Probe applications of THz Spectroscopy: The case of Elettra, Bessy-II, and SPARC