発表資料（PDF）

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
Outline
zIRSR + THzSR?
¾characteristics
¾IRSR + THzSR beamlines in the world
zApplications of THzSR
¾Conventional use
¾Microscopic use
zFuture
zDoes we need intense IR + THz sources?
Advantage of IRSR compared with
ordinary sources
z High brilliance
Ordinary source
（globar lamp etc.）
¾ Excellent for spectromicroscopy
IRSR
z Broadband
Electron beam
¾ Useful for spectroscopy
z Linear/circular polarization
¾ Crystallic asymmetry，
Molecular orbital,
polar direction，MCD
Globar
IR-SR
Intensity
25 : 1
z Pulse (sub-pico-second)
¾ Time structure
-50
0
0
X (µm)
50 -50
50
-50
0
0
50 -50
50
Y (µm)
THzSR+IRSR beamline in the world
Japan
UVSOR-II 6B THz+IR, multipurpose, microscopy, MCD
SPring-8 43IR IR, microscopy under extreme conditions
USA
NSLS
U2A 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
SOLEIL
UK
SRS
13.3
IR, microscopy, surface science
Diamond
Sweden MAX I
073 IR, high resolution (gas)
Germany ANKA
IR Edge radiation
BESSY II
IR, microscopy, THz-CSR
Italy
DAΦNE SINBAD THz+IR
Elletra
IR
Red: THz
Taiwan SRRC
IR, microscopy
Blue: IR.
Switzerland SLS
IR microscopy
ESRF
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 stage
for MM
Intensity and brilliance of IRSR
compared with a globar lamp
Brilliance
BL6B(IR)
(I=500mA)
Photon flux (ph/s/0.1% b.w.)
15
10
UVSOR-II
BL6B
old-BL6A1
(I=300mA)
SPring-8 BL43IR
(I=100mA)
14
10
Black body source
(for large sample)
(1400K, φ5mm, 0.015sr)
13
10
SPring-8
BL43IR
12
10
-3
10
-2
10
Black body source
(for microscope)
(1400K, φ1mm, 0.015sr)
10
-1
hν (eV)
0
10
Globar lamp
Brilliance @ first focusing point
2
2
(ph/s/mm /mrad /0.1%b.w.)
Intensity
10
12
SPring-8
BL43IR
SPring-8
I=100mA
BL43IR
10
10
11
BL6B
UVSOR-II
I=500mA
10
BL6B
old-BL6A1
I=300mA
10
9
Black body
(T=1400K)
8
10 -3
10
10
-2
10
-1
hν (eV)
Globat lamp
10
0
10
1
End stations of BL6B
at UVSOR-II
Bending #6
Magic mirror
To BL6U
Diamond /
z-cut Quartz
window
JASCO
FARIS-1
THz microscope
Bruker
IFS66v/S
Refection-absorption
spectroscopy station
0
500
1000
This chamber can be removed for the other
experiments (IR-MCD, FIR-RAS and so on).
Old data
Hot carriers in SmB6
BL6B
(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
1
Impurity state
Main gap
10
Large spectral
change is due to the
thermally excited
carriers across the
small 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
window
JASCO
FARIS-1
THz microscope
Bruker
IFS66v/S
Refection-absorption
spectroscopy station
0
500
1000
THz spectroscopy under
pressures
Microscope
•Horizontal optical pass
•Energy range
•Laboratory: 50 meV ∼ 1.2 eV
•UVSOR-II BL6B: 5 meV ∼ 50 meV
Microsope @ BL6B
Diamond anvil pressure cell
Spatial resolution of microscope in
the THz region at BL6B
• Pressure media：Apiezon grease N
• Pressure is measured by a ruby
fluorecence method.
reflection
100µm
Sample
1.0 mm
Gasket
0.5 mm
Ruby
Pressure Media
Diamond anvil cell
DAC
UVSOR Facility, Institute for Molecular Science
Pressure dependence of R(ω ) in SmS
[ T. Mizuno, SK et al. ]
1
1.45 GPa
EG
DOS
Exp.
Calc.
FD
1
1
TO phonon
0.85 GPa
E
EF
0
0.65 GPa
10
run0
Two phase
run1
run2
-1coexistence?
1
Reflectivity
1
1.0
0.45 GPa
Drude
from carriers
0.20 GPa
0.5
Neff (/SmS)
10
Black phase
-2
10
-3
Golden
phase
EG~850K
10
1 atm
0.0
EG~1000K
-4
50
100
Photon energy (meV)
10
0.0
0.5
Pressure (GPa)
1.0
Scientific program at BL6B
z Electrodynamics of solids @
multi-extreme conditions
¾ Very low temperature (~0.4K)
¾ High pressures (~20GPa)
¾ High fields (~6T)
z THz microspectroscopy
z FIR-RAS of adsorbed molecules
z THz spectroscopy of protains
z THz excitation with coherent SR.
¾ 103~104 higher intensity than the
present 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 the
number 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 10
1077
Undulator
CSR from
slicing
105
Laser 100000.
1000
103
N・f(1/λ)
IR- BL
CSR from
whole bunch
101
Incoherent SR
10
0.1
10-1
0.1
0.5
5
10
0.1
0.5 11
5 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
Short
pulse
The dip is made by laser.
Onset
Long
pulse
0
10
20
-1
Wavenumbers (cm )
Onset shifts to the lower
wavenumber side with increasing
pulse width.
This is the evidence of the CSR
originates from the dip induced by
laser.
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
2
High 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.
zFuture
¾We need intense IR + THz light.
– Further advanced spectroscopy. (SNOM, )
– THz pump – VIS, ｘ-ray,,,, probe experiment.
– Chemical reaction.
– Etc.