Return to main page

LIGO

Topics

• Introductory
  • I've gone to a number of LIGO lectures, and picked up some fun documentation

    Handouts 1st-GW150914.pdf - Was Einstein right about strong gravity? Using Gravitational Waves ... 2nd-GW151226.pdf - GW151226: Observation of Gravitational Waves ... ObservationGW.pdf - General, Observation of Gravitational Waves ... Quantum Enhanced LIGO Detector Sets New Sensitivity Record Research paper Stretched.pdf - If light waves are stretched by gravitational waves, how ... Video “100 Years of Gravitational Waves: The Observation of a Binary Black Hole Collision" - Rainer Weiss, (MIT) Sept 20, 2017 Sackler Lecture: Exploration of the Universe with Gravitational Waves - Rainer Weiss, (MIT) Feb 15, 2018 - he stresses thinking of these as phase modulated side bands at the frequency of the gravitational wave.
• Financing, Organization
  • LIGO Richard Isaacson - NSF - long term funding, Marcel Bardon boss,
    "Detecting gravitational waves takes a team and long-game perspective"
• Frequency Response, and low noise frequencies
• Light
  • laser - why this frequency
    • Uses 1064 nm light from a Nd:YAG laser.
  • stabilization of laser
    • The Pound–Drever–Hall (PDH) technique is a widely used and powerful approach for stabilizing the frequency of light emitted by a laser by means of locking to a stable cavity.
    • Laser Frequency and intensity Stabilization for Advanced LIGO, Evan Hall (local copy)
    • LIGO's Laser
  • squeezed light
    • Squeezed coherent state Wikipedia
    • Squeezed states of light - RP Photonics
    • Squeezed light - Vladimir Braginsky - variation of radiation pressure on the mirror variation diffraction pattern - pair of photons out of phase ... something
      A memorial to Vladimir Braginsky, who among other things, searched for "underwater rocks" that might limit LIGO.
    • GEO600 has been improving the science and art of squeezed light as part of their research to lower noise in interferometers.
    • A 1997 paper in Nature Measurement of the quantum states of squeezed light
• LIGO Techie sites
  • Caltech's
  • MIT's
  • "Sister facilities"
    • VIRGO Italy
    • GEO600 Germany
    • TAMA300 Japan
    • LIGO-India India
    • LISA-ESA, LISA-NASA
• Observing environment and "Veto" intervals of time
• People
• Transverse waves
• Test masses and Suspensions
  • "Mirrors That Hang on Glass Threads" video
  • "Active vibration isolation using a Suspension Point Interferometer" - .pdf - 2006
  • "Active vibration isolation using a Suspension Point Interferometer" - slides of lecture - 2004
• Ultimate limits of Gravitational Wave detection on earth, turbulent air masses, ...
  - Bury deep as in Japan ?
• Versions of Gravitational Wave detectors
  • Weber bar aluminum "bar" with strain detectors glued on it
  • interferometer
    • first LIGO
    • Advanced LIGO
    • A+, Enhancing Advanced LIGO -G1601435 paper
    • LIGO Voyager -G1700848 paper
    • LIGO Einstein-b ??

  ---

• Current status
  The two LIGO sites were shut down (October 2017) for the squeezed light upgrade I don't understand, And ?other things ... Hope they return to service late 2018.

That's all for now folks -

Started March 2018
Updated through April 2018

---

Notes from Ray Weiss's lecture

1. this is just like the Heisenberg microscope that you learned about in quantum mechanics, but not with an electron, but with a 40 Kg Test Mass.