0.Abstract

1
????? (?????????????)
?? ?? ???? ?????? ??????
2011/6/24 _at_???????????
2
0.Abstract

• ?????????????????
• ?????????
• (1)??????
• (2)Cavity??????????
• ???2???????????????

3
Contents

• 1. Gravitational wave detection
• 2. Frequency stabilization
• 3. Summary

4
1. Gravitational wave detection

• What is the gravitational wave ?
• 1915 A. Einstein General theory of
  Relativity
• Gravitation is
  curvature of space-time.
• 1916 A. Einstein Prediction of
  gravitational wave
• Gravitational wave is
  ripple of space-time.

A. Einstein, S. B. Preuss. Akad. Wiss. (1916) 688.
Wikipedia (A. Einstein, English)
5
1. Gravitational wave detection

• Gravitational wave
• Speed is the same as that of light.
• Transverse wave and two polarizations

http//spacefiles.blogspot.com
6
1. Gravitational wave detection

• Interaction of gravitational wave is too weak !
• Artificial generation is impossible !
• No experiment which corresponds to
• Hertz experiment
  for electromagnetic wave
• Astronomical events
• Strain (Change of length)/(Length) h
  10-21
• (Hydrogen atom)/(Distance between Sun and
  Earth)
• No direct detection until now
• 
  

7
1. Gravitational wave detection

• Indirect detection of gravitational wave
• Binary pulsar
• (R.A. Hulse and J.H. Taylor,
• 
  Astrophysical Journal 195 (1975) L51.)
• Generation of gravitational wave
• Energy emission
• Change of period of binary
• Observed change of period agrees with
  theoretical
• prediction by radiation formula of
  gravitational wave.
• J.H. Taylor et al., Nature 277 (1979) 437.
• 
  

8
1. Gravitational wave detection

• Recent result
• 
  

J.M. Weisberg and J.H. Taylor, ASP Conference
Series, 328 (2005) 25 (arXivastro-ph/0407149).
8
9
1. Gravitational wave detection
Web site of Nobel foundation
10
1. Gravitational wave detection
No direct detection until now

• What is the motivation ?
• Physics Experimental tests for theory
  of gravitation
• Astronomy New window for astronomical
  observation
• 
  Gravitational wave astronomy
• 
  

11

1. Gravitational wave detection

• Gravitational wave astronomy Burst source
  Supernova

• Mechanism of the core-collapse SNe still unclear
• Shock Revival mechanism(s) after the core bounce.

GWs generated by a SNe should bring
information from the inner massive part of the
process and could constrains on the core-collapse
mechanisms.
M. Punturo, GWDAW Rome 2010
12
1. Gravitational wave detection
Gravitational wave astronomy Burst source
Compact binary coalescence Neutron star, Black
hole
quasi-mode oscillation
coalescence
chirp signal
-300Hz
-1kHz
K. Kuroda Fujihara seminar (2009)
msec
New standard candle for measurement of
distance Equation of state at high density,
formation black hole
13
1. Gravitational wave detection
There are a lot of kinds of detectors !
Resonant detector Interferometer (on
Earth) Interferometer (Space) Doppler
tracking Pulsar timing Polarization of cosmic
microwave background and so on
Frequency range 10-18 Hz 108 Hz
14
1. Gravitational wave detection
Interferometer (on Earth) Gravitational wave
changes length difference of two arms.
Frequency 10 Hz 10 kHz
15
1. Gravitational wave detection
All current interferometers have Fabry-Perot
cavities.
16
World wide network for GW astronomy
LIGO(I) Hanford
GEO 600
GEO HF
Adv. LIGO (under construction since 2008)
LCGT
TAMA/CLIO LCGT, Budget request
Virgo
Adv. Virgo (design)
LIGO(I) Livingston
AIGO (budget request)
ET (planed)
A network of detectors is indispensable to
position the source.
By K. Kuroda (2009 May Fujihara seminar)
17
1. Gravitational wave detection
LIGO (U.S.A.)
4 km, Hanford and Livingston (3000 km distance)
(U.S.A.)
S. Kawamura, Classical and Quantum Gravity 27
(2010) 084001.
17
18
1. Gravitational wave detection
VIRGO (Italy and France)
3 km, Pisa (Italy)
S. Kawamura, Classical and Quantum Gravity 27
(2010) 084001.
18
19
1. Gravitational wave detection
GEO (Germany and U.K.)
600 m, Hannover (Germany)
S. Kawamura, Classical and Quantum Gravity 27
(2010) 084001.
19
20
1. Gravitational wave detection
TAMA (Japan)
300 m, Tokyo (Japan)
S. Kawamura, Classical and Quantum Gravity 27
(2010) 084001.
21
1. Gravitational wave detection
CLIO (Japan)
100 m, Kamioka (Japan)
S. Kawamura, Classical and Quantum Gravity 27
(2010) 084001.
22
1. Gravitational wave detection
First generation (Current) LIGO (U.S.A.),
VIRGO (Italy and France), GEO (Germany and
U.K.), TAMA (Japan), CLIO (Japan) Second
generation (Future) Advanced LIGO, Advanced
VIRGO, GEO-HF,
AIGO(Australia), LCGT (Japan) Third
generation (Future) Einstein Telescope
(Europe)
23
1. Gravitational wave detection
Sensitivity of interferometer
1st generation (LIGO,VIRGO)
10 times
2nd generation
10 times
3rd generation
24
1. Gravitational wave detection
Second generation Observation 2017 ?
We can expect first detection !
Advanced LIGO, Advanced VIRGO, GEO-HF
Upgrade of LIGO, VIRGO, and GEO AIGO
(Australia)Budget is requested.
Similar to Advanced LIGO LCGT (Japan)
Cryogenic technique (Mirror
temperature is 20K, small thermal motion)
Underground site (small seismic motion)

25
1. Gravitational wave detection
Third generation Observation 2026 ?
Einstein Telescope (Europe)
30 km vacuum tube in total
Cryogenic technique Underground site (small
seismic motion)
26
Location of LCGT
3 km, Kamioka (Japan)
LCGT is planed to be built underground at
Kamioka, where the prototype CLIO detector is
placed.
By K. Kuroda (2009 May Fujihara seminar)
27
1. Gravitational wave detection
???LCGT???(http//gwcenter.icrr.u-tokyo.ac.jp/) 2
010?6??????????????????????????????????????????
2011?3???????????(??)? 2011?6?LCGT?????(630????
)? 2011?7 or 8?LCGT??????
28
1. Gravitational wave detection
????? 2010/10-2014/9 iLCGT (????????)
1????????? 2014/10-2017/3
bLCGT(????????) 2017/4- ???????
29
1. Gravitational wave detection
?????? 2011?7??? LCGT??????
30
1. Gravitational wave detection
Interferometric gravitational wave detector
Mirrors must be
free and are suspended.
S. Kawamura, Classical and Quantum Gravity 27
(2010) 084001.
31
1. Gravitational wave detection
Thermal noise of suspension and mirror
32
1. Gravitational wave detection
Fluctuation-Dissipation Theorem
Relation between thermal noise
and mechanical loss in suspension and
mirror

Amplitude of thermal noise is proportional to
(T/Q)1/2.
In general, Q (inverse number of magnitude of
Dissipation,f) depends on T (temperature).
33
1. Gravitational wave detection
Mirror thermal noise Two kinds of
mechanical dissipation Thermoelastic
damping Inhomogeneous strain
Temperature gradient (via thermal
expansion) Heat flow
Dissipation
Structure damping Unknown
mechanism Almost no frequency
dependence
34
1. Gravitational wave detection
Mirror consists of not only substrate,
but
also reflective coating !
Thermoelastic damping Heat flow in
substrate Substrate thermoelastic noise
Heat flow between substrate and coating

Thermo-optic noise Structure damping Structure
damping in substrate Substrate Brownian noise
Structure damping in coating Coating Brownian
noise
34
35
1. Gravitational wave detection
Temperature dependence of mirror thermal noise in
LCGT
Below 20 K Thermal noise is sufficiently small
for LCGT.
35
36
2. Frequency stabilization
Thermal noise is fundamental noise of
gravitational wave detection. How about the
other fields ?
Cavity as reference for laser
frequency stabilization
Current best laser frequency stabilization
with rigid cavity at room temperature
is limited by
thermal noise of mirrors.
K. Numata et al., Physical Review Letters 93
(2004) 250602.
37
2. Frequency stabilization
Hot paper (ISI Web of Knowledge)
1 paper every 3 weeks ! (until 18 June 2011)
38
2. Frequency stabilization
0.1Hz/rtHz(1Hz/f)1/2 (10mHz-1Hz) Allan deviation
410-16 (10mHz-1Hz)
39
2. Frequency stabilization
????(Case 1, 2011?????one of the best records)
B.C. Young et al., Physical Review Letters 82
(1999) 3799. Spacer(ULE)?????????????????? ?(ULE
)?????????????? ??fused silica????coating?????
40
2. Frequency stabilization
????(2011?????one of best records) B.C. Young et
al., Physical Review Letters 82 (1999) 3799.
??????????? (1)Cavity?????? (2)???????????
???2????????????????
???factor?????? (3)Coating
mechanical loss??????? (4)Cryogenic technique
41
2. Frequency stabilization
(3)Coating mechanical loss???????
Old summary of coating mechanical loss
(Ta2O5/SiO2)
Similar results (same order of
magnitude)
f is on the order of 10-4.
Loss angle 1/Q
K. Yamamoto et al., Physical Review D 74 (2006)
022002.
41
42
2. Frequency stabilization
(3)Coating mechanical loss??????? (a)TiO2 doping
(Ta2O5) TiO2 20 loss??

G. Harry et al., Classical and Quantum Gravity 24
(2007) 405.
43
2. Frequency stabilization
(3)Coating mechanical loss??????? (b)Ta2O5/SiO2
??????? Niobia, Hafnia, SilicaTitania,
Zirconia, Almina, . Ta2O5/SiO2
????????????? f is on the order of 10-4.
Amorphous silicon X. Liu and R.O. Pohl,
Physical Review B 58(1998)9067. f is on the
order of 10-7 10-5 . ???1100nm???????????

44
2. Frequency stabilization
(3)Coating mechanical loss??????? (b)Ta2O5/SiO2
??????? AlxGa1-xAs (Small oscillator)

f 210-4 at 300K, 510-5 at 4K
G.D. Cole et al., Applied Physics Letters 92
(2008) 261108.
f 110-5 at 20K
G.D. Cole et al., 2010 IEEE 23rd International
Conference on Micro Electro Mechanical Systems
(MEMS). Pages 847 850
45
2. Frequency stabilization
(4)Cryogenic technique

????(Case 1, 2011?????one of the best
records) ?(ULE)?????????????? ??????????coating???
?? 1/3? Coating??????????????4K??????1/10??

4 K Thermal noise is 30 times smaller (Coating
dominant).
45
45
45
46
2. Frequency stabilization
(4)Cryogenic technique

4 K Thermal noise is 30 times smaller (Coating
dominant).
300 K 0.1Hz/rtHz(1Hz/f)1/2 (10mHz-1Hz)
Allan
deviation 410-16 (10mHz-1Hz)
4 K 3 mHz/rtHz(1Hz/f)1/2 (10mHz-1Hz)
Allan deviation
110-17 (10mHz-1Hz)
47
2. Frequency stabilization
(4)Cryogenic technique
Material of mirror and spacer
Structure damping (frequency independent) in
substrate
Fused silica can not be used. Sapphire or
Silicon are good.
Q value measurement T. Uchiyama et al., Physics
Letters A 261 (1999) 5-11. R. Nawrodt et al.,
Journal of Physics Conference Series 122 (2008)
012008. C. Schwarz et al., 2009 Proceedings of
ICEC22-ICMC2008.
47
48
2. Frequency stabilization
(4)Cryogenic technique
Laser frequency stabilization with rigid cavity
at 3 K
Universität Konstanz
S. Seel et al., Physical Review Letters 78 (1997)
4741.
48
49
2. Frequency stabilization
(4)Cryogenic technique
At 3 K
2.510-15
Universität Konstanz
NIST
Best record at room temperature 410-16 (limited
by substrate Brownian noise)
B.C. Young et al., Physical Review Letters 82
(1999) 3799.
50
2. Frequency stabilization
(4)Cryogenic technique
At 4 K
110-15
Some progress
H. Mueller et al., Physical Review Letters 91
(2003) 020401.
51
2. Frequency stabilization
(4)Cryogenic technique
Laser frequency stabilization with rigid cavity
at cryogenic temperature
should be better ! Allan deviation 110-17
(limited by coating Brownian noise)
Experiment 110-15
Development is in progress (This is not a perfect
list).
Universität Konstanz, Humboldt-Universität zu
Berlin, Heinrich-Heine-Universität Düsseldorf?,
Physikalisch-Technischen Bundesanstalt Universi
ty of Tokyo (Tsubono lab.)
51
52
2. Frequency stabilization
(4)Cryogenic technique Coating dominant
source Temperature dependence ?
University of Tokyo
Loss angle is almost independent of temperature.
K. Yamamoto et al., Physical Review D 74 (2006)
022002.
53
2. Frequency stabilization
(4)Cryogenic technique Coating dominant
source Temperature dependence ?
Peak at 20 K ?
Glasgow University
I. Martin et al., Classical and Quantum Gravity
25(2008)055005.
53
54
2. Frequency stabilization
(4)Cryogenic technique Coating dominant
source Temperature dependence ?
Annealing suppresses (Ta2O5) peak.
Glasgow University
I. Martin et al., Classical and Quantum Gravity
27(2010)225020.
55
2. Frequency stabilization
(4)Cryogenic technique Coating dominant
source Temperature dependence ?
TokyoJAE GlasgowCSIRO
Vendor ?
M. Abernathy et al., CWADW 2011
http//agenda.infn.it/getFile.py/access?contribId
56sessionId15resId2materialIdslidesconfId
3351
56
2. Frequency stabilization
(4)Cryogenic technique Coating dominant
source Temperature dependence ?
????????????????????? ????coating?mechanical
loss????????? ????????! LCGT?????????????????
?? (JAE???????????)
57
2. Frequency stabilization
Optical Coatings and Thermal Noise
in
Precision Measurements, ed. by Gregory
Harry, Riccardo Desalvo,
and Timothy
Bodiya, Cambridge University Press, in
press.
2012?1?????
???????????????????? ?????????????
58
2. Frequency stabilization
????
59
2. Frequency stabilization
????
60
2. Frequency stabilization
????
????????????????????
61
3.Summary
(1)???????????? (2)LCGT ?????????????
???????????????20K???? (3)Cavity????????????????
?????????????????
0.1Hz/rtHz(1Hz/f)1/2 (10mHz-1Hz)
Allan deviation
410-16 (10mHz-1Hz)
62
3.Summary
(4)????????????????????? (a)Coating mechanical
loss??????? (i)TiO2 doped Ta2O5/SiO2
Loss?????? (ii)Ta2O5/SiO2 ???????
Amorphous silicon, AlxGa1-xAs ??????
62
63
3.Summary
(4)????????????????????? (b)Cryogenic technique
4 K Thermal noise is 30 times smaller. 4 K
3 mHz/rtHz(1Hz/f)1/2 (10mHz-1Hz)
Allan deviation 110-17
(10mHz-1Hz) ??spacer???????????????
????coating?mechanical loss? ????????????????!
?????????????
64
???????????????