1 Lasers and Optics of Gravitational Wave Detectors Rick Savage LIGO Hanford Observatory.
Searching for gravitational waves with lasers (LIGO)
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Transcript of Searching for gravitational waves with lasers (LIGO)
Searching for gravitational waves with lasers (LIGO)
Rick SavageCaltech
LIGO Hanford Observatory - Richland, WA
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Transferred to UCLA in Physics in 1974 Jan 1975
» Started working for F. Chen and N. Luhmann as undergraduate lab assistant (with Doug Cook)
– Alain Semet, John Turcek, Steve Obenschain, Jim Holt, Mark Herbst, et al.
1976-1986 Plasma diagnostics» N. Luhmann, T. Peebles, H. Fetterman, et al.
– Microtorr, macrotorr, UT FRC, FIR lasers, CO2 lasers
1986 – 1992 Laser / Plasma interactions » Graduate school in EE at UCLA – Chan Joshi» Masters thesis – Degenerate four-wave mixing in heated CO2 gas» PhD thesis – Frequency upshifting of electromagnetic radiation via an
underdense relativistic ionization front 1992 – present
» LIGO project – Caltech until 1997 then LIGO Hanford Observatory in Richland, WA
Black holes and time warps
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http://www.einsteinsmessengers.org/
LIGO: Laser Interferometer Gravitational-wave Observatory
3002 km(L/c = 10 ms)
Caltech
MIT
• Managed and operated by Caltech & MIT with funding from NSF
• Goal: Direct observation ofgravitational waves
•Open an new observationalwindow on the Universe
Livingston, LA
Hanford, WA
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LIGO Scientific Collaboration
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General relativity – gravitational waves
Laser Interferometer
GW: oscillating quadrupolar strain in spacetime
“Matter tells spacetime how to curve.Spacetime tell matter how to move.”
J. A Wheeler
Albert Einstein1916
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Detection of graviational waves
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Michelson interferometer- differential length change sensor
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Pulsar System PSR 1913 + 16 (R.A. Hulse, J.H. Taylor Jr, 1975)
Orbit will continue to decay over the next ~300 million years, until coalescence
Gravitational wave emission will be strongest near the end
(Weisberg, Taylor)
Do they exist? Indirect evidence
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Capturing the waveform
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Sketch:Kip Thorne
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Sources
Credit: AEI, CCT, LSU
Coalescing Binary Systems• Neutron stars,
low mass black holes, and NS/BS systems
Credit: Chandra X-ray Observatory
‘Bursts’ galactic asymmetric core collapse supernovae
cosmic strings
???
NASA/WMAP Science Team
Cosmic GW background stochastic, incoherent background
Casey Reed, Penn State
Continuous Sources Spinning neutron stars
probe crustal deformations
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Ligo detectors
Laser
4 km-long Fabry-Perotarm cavity
recyclingmirror test masses
beam splitter
Power RecycledMichelsonInterferometerwith Fabry-PerotArm Cavities
signal
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iLigo hardware
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S5 Science Run Nov 2005 – Oct 2007
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No detections (so far) - data still being analyzed Astrophysical results – upper limits
“If LIGO didn’t detect it, then it can’t be bigger than …”» CRAB pulsar – “no more than 4 percent
of the energy loss of the pulsar is caused by the emission of gravitational waves.” (ApJL 683, L45)
» Gamma ray burst GRB 070201 – LIGO “results give an independent wayto reject hypothesis of a compact binaryprogenitor in M31”(ApJ 2008, 681, 1419)
» Upper limit on the stochastic gravitational wave background(http://www.nature.com/nature/journal/v460/n7258/pdf/nature08278.pdf)
Scientific results of S5 run
Credits for X-ray Image: NASA/CXC/ASU/J. Hester et al.Credits for Optical Image: NASA/HST/ASU/J. Hester et al.
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108 ly
Enhanced LIGO LIGO today
Credit: R.Powell, B.Berger
Adv. LIGO
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10 W to 200 W laser source
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Single to quadruple pendulum
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Passive to active vibration isolation
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Time warps UCLA Laser/Plasma interactions
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LIGO Scientific Collaboration
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Started as a collaboration between Caltech and MIT
Goal: direct observation of gravitational waves Open a new observational window on the Universe
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Laser Interferometer Gravitational-wave Observatory
3030 km(±10 ms)
CALTECHPasadena
MITBoston
HANFORDWashington
LIVINGSTONLouisiana
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South-central Washington» Where Columbia, Yakima, and Snake rivers converge
LIGO Hanford Observatory
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Frank’s thinking ….. inflatable kiyak ? ….
LIGO
credit: Google Maps
Doug CookColumbia River
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closer look – more lasers and optics
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