テラヘルツ放射光の現状と大強度CSRの利用
木 村 真 一自然科学研究機構 分子科学研究所
極端紫外光研究施設（UVSOR）
ERL研究会「コンパクトERLが拓く世界」@KEK 070709-10

OutlinezIRSR + THzSR?
¾characteristics¾IRSR + THzSR beamlines in the world
zApplications of THzSR¾Conventional use¾Microscopic use

zFuturezDoes we need intense IR + THz sources?

Advantage of IRSR compared withordinary sourcesz High brillianceOrdinary source（globar lamp etc.）¾ Excellent for spectromicroscopy

IRSRz Broadband

Electron beam

¾ Useful for spectroscopyz Linear/circular polarization¾ Crystallic asymmetry，
Molecular orbital,
polar direction，MCDGlobarIR-SR

Intensity

25 : 1z Pulse (sub-pico-second)¾ Time structure-5000X (µm)

50 -5050-500050 -50

50

Y (µm)THzSR+IRSR beamline in the worldJapan

UVSOR-II 6B THz+IR, multipurpose, microscopy, MCD
SPring-8 43IR IR, microscopy under extreme conditions
USANSLSU2A IR, microscopy under high pressure (geology)
U2B IR, microscopy for biology
U4IR THz+IR, surface science
U10A IR, multipurpose (solid state physics)
U10B IR, multipurpose, wide energy range
U12IR THz+IR, pump-probe (solid state physics)
ALS
1.4.2 IR, multipurpose, surface science
1.4.3 IR, microscopy (biology)
SRC
031 IR, microscopy
France super-ACO SIRLOIN, IR, multipurpose
SOLEILUK
SRS
13.3
IR, microscopy, surface science
DiamondSweden MAX I
073 IR, high resolution (gas)Germany ANKA
IR Edge radiation
BESSY IIIR, microscopy, THz-CSR
Italy
DAΦNE SINBAD THz+IR
ElletraIR
Red: THz
Taiwan SRRC
IR, microscopy
Blue: IR.
Switzerland SLS
IR microscopyESRF
IR, microscopy
China NSRL, Canada CLS,,
under consideration

Reconstructed IR+THz beam line（BL6B） at
UVSOR-II (since 2004)
Acceptance angle of SR
From 80(H) x 60(V) mrad2
To 215(H) x 80(V) mrad2
UVSORUVSOR-II storage ring

Bending duct

6-axes pulse
motor stagefor MM

Intensity and brilliance of IRSR
compared with a globar lamp
Brilliance
BL6B(IR)(I=500mA)

Photon flux (ph/s/0.1% b.w.)

1510

UVSOR-II
BL6B

old-BL6A1(I=300mA)
SPring-8 BL43IR(I=100mA)

1410

Black body source(for large sample)(1400K, φ5mm, 0.015sr)

1310

SPring-8
BL43IR

1210-3

10-210Black body source(for microscope)(1400K, φ1mm, 0.015sr)
10-1hν (eV)010

Globar lamp

Brilliance @ first focusing point
22(ph/s/mm /mrad /0.1%b.w.)

Intensity
1012

SPring-8
BL43IR
SPring-8
I=100mA

BL43IR

101011BL6B
UVSOR-II
I=500mA

10BL6B

old-BL6A1
I=300mA
109Black body
(T=1400K)
810 -31010-210-1hν (eV)Globat lamp

100101

End stations of BL6B
at UVSOR-II

Bending #6
Magic mirror

To BL6U
Diamond /z-cut Quartz
windowJASCO
FARIS-1

THz microscope

Bruker
IFS66v/S
Refection-absorption
spectroscopy station
0500

1000

This chamber can be removed for the otherexperiments (IR-MCD, FIR-RAS and so on).

Old data

Hot carriers in SmB6BL6B
(UVSOR-II)In Lab.
(mercury lamp)

Not clear?

1.00

SmB6
T=80K

0.95

Reflectivity

Clear[ S. K. et al., Phys. Rev. B 50, 1406 (1994). ]
0.90

T=20K

0.85
T=5K

1Impurity state

Main gap
10Large spectralchange is due to thethermally excitedcarriers across thesmall energy gap.
DOS
17meV

Photon energy (meV)EFEnd stations of BL6B
at UVSOR-II

Bending #6
Magic mirror

To BL6U
Diamond /z-cut Quartz
windowJASCO
FARIS-1

THz microscope

Bruker
IFS66v/S
Refection-absorption
spectroscopy station
0500

1000

THz spectroscopy underpressures
Microscope•Horizontal optical pass
•Energy range•Laboratory: 50 meV 〜 1.2 eV•UVSOR-II BL6B: 5 meV 〜 50 meVMicrosope @ BL6B

Diamond anvil pressure cell

Spatial resolution of microscope inthe THz region at BL6B

• Pressure media：Apiezon grease N• Pressure is measured by a rubyfluorecence method.
reflection

100µmSample
1.0 mmGasket
0.5 mmRuby
Pressure Media

Diamond anvil cellDAC

UVSOR Facility, Institute for Molecular Science

Pressure dependence of R(ω ) in SmS[ T. Mizuno, SK et al. ]11.45 GPa

EGDOS

Exp.
Calc.

FD

1
1TO phonon

0.85 GPaE

EF00.65 GPa

10

run0Two phaserun1
run2-1coexistence?

1Reflectivity

1
1.00.45 GPa

Drudefrom carriers
0.20 GPa

0.5Neff (/SmS)

10Black phase-210-3Goldenphase
EG~850K101 atm

0.0EG~1000K-450100

Photon energy (meV)

100.00.5

Pressure (GPa)1.0

Scientific program at BL6Bz Electrodynamics of solids @multi-extreme conditions¾ Very low temperature (~0.4K)¾ High pressures (~20GPa)¾ High fields (~6T)

z THz microspectroscopyz FIR-RAS of adsorbed moleculesz THz spectroscopy of protains
z THz excitation with coherent SR.
¾ 103~104 higher intensity than thepresent IRSR.

今後の動向？ （私感）
zより速く，より高く，より遠くへ。

(オリンピックではないけれど，)¾時分割¾より高い空間分解能– 近接場分光など例）化学変化や相変化のビデオ撮影
例）パルス超高磁場によるスペクトル変化¾高磁場，高圧力，高電圧，極低温，，，z異次元の世界へ。
¾プローブ光だけではなく励起光としての利用。
¾化学反応の赤外光による制御，など。

大強度が必要。

Coherent Synchrotron Radiation （CSR）
Wavelength (λ)
Electromagnetic
wave
Bunch length » λ+Bunch length ≤ λ→ no interference
The intensity is
proportional to thenumber of electron (Ne).

＝→ perfect interference
The intensity is proportional
to Ne2.

→ partial interferenceIntense CSR induced by a laser bunch slicing[M. Shimada et al., submitted.]

UVSOR-BL6B IR Beamline(S. Kimura et al., AIP Conf. Proc. 705 (2003),

1. ｴ 101077

Undulator

CSR from
slicing105
Laser 100000.
1000
103
N・f(1/λ)IR- BLCSR from
whole bunch

101
Incoherent SR
100.1
10-1
0.1
0.5
5100.1
0.5 115 10
Wave number (cm-1)

25cm-1

Coherent Terahertz Pulses by Bunch Slicing[ M. Katoh et al., Proc. EPAC06, 3377 (2006). ]Stable and periodic.

The width originates from the InSb
hot electron detector response.

CSR Intensity (arb. units)

Laser pulse width dependence[ M. Katoh et al., Proc. EPAC06, 3377 (2006). ]of CSR spectrum

Laser width =160 fsec
320 fsec
530 fsec
710 fsec

Shortpulse

The dip is made by laser.

Onset

Onset shifts to the lower
wavenumber side with increasing
pulse width.

20This is the evidence of the CSR
originates from the dip induced bylaser.

Longpulse
010-1

Wavenumbers (cm )Average power of CSR
UVSOR-II BL6B

Commercial
THz source

SPring-8 BL43IR

Application of CSR @ BESSY-II(Conventional use)

Use of intense sub-THz light[M. Ortolani et al., PRL 97, 097002 (2006).]

THz SNOM @ BESSY-II(Microscopic use)
[U. Schade et al., APL 84, 1422 (2004).]λ ∼ 500 µm

VISIBLE image

THz image[G.L. Carr et al., Nature, 420, 153 (2002).]

Intense CSR from ERL @ KEK[K. Harada @ KEK]

0.01ps
0.1ps
1ps

-1

Power (W/cm ) in 100x100mrad

2High power CW THz sources[M. Tonouchi, nature photonics 1, 97 (2007).]

Conclusion + outlook
zPresent THzSR + IRSR
¾High intensity + high brilliance.
¾Applications are mainly conventional use.
¾New advanced spectroscopies were produced.

zFuture¾We need intense IR + THz light.
– Further advanced spectroscopy. (SNOM, )– THz pump – VIS, ｘ-ray,,,, probe experiment.
– Chemical reaction.
– Etc.