eLIGO Input Optics Characterization and Performance

1

• eLIGO Input Optics Characterization and
  Performance
• Kate Dooley
• University of Florida

2
Input Optics
Recycling mirror

• EOMs through MMT

Ref cavity
Faraday isolator
EOMs
Laser
Mode matching telescope
Pre mode cleaner
Mode cleaner
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IO Upgrade

• Why?
• 3x increase in laser power
• Commission advLIGO designs
• Fix problems found during iLIGO
• Tasks
• New Faraday Isolator
• Clean mode cleaner
• Adjust mode matching telescope
• New electro-optic modulators

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New Layout
REFL
SM
MMT1
0.65W
Faraday Isolator
to RM
MC3
MMT3
MC1
PSL
For 1W into the vacuum
7 loss
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Mode Cleaner Absorption

• Absorption (ppm)

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Mode Cleaner Cavity Pole
swept-sine
MC
Laser
PD1
PD2
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Faraday Isolator

• Higher isolation ratio
• Multiple high extinction ratio polarizers
• Multiple TGGs, Quartz rotator
• Higher transmission
• High transmission polarizers
• Low absorption TGG
• Lower thermal drift
• Increased thermal contact with crystals
• Less thermal lensing
• Negative lens DKDP

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Faraday Isolator Design
REFL
DKDP QR HWP
CWP TFP TGG TGG
CWP
Faraday rotator
p-pol gt 22.5 - 67.5 22.5 22.5 gt
p-pol s-pol lt 22.5 67.5 22.5 - 22.5 lt
p-pol
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Advanced Faraday Isolator
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Isolation Ratio
Prefl
s-pol
Pout
p-pol
Pin
p-pol
p-pol
Faraday Isolator
LLO data
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Thermal Drift
Upper limit of 3 beam diameter movement on WFS
IN AIR
LLO data
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Power Budget
REFL
0.74W
SM
MMT1
0.9W
Faraday Isolator
0.83W
to PRM
MC3
MMT3
MC1
PSL
For 1W into the vacuum
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Summary
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Acknowledgements

• Rupal Amin
• Muzammil Arain
• Betsy Bland
• Valera Frolov
• Dan Hoak
• Ketia Kawabe
• Mike Landry
• Antonio Lucianetti
• Rodica Martin
• Guido Mueller
• Volker Quetschke
• Dave Reitze
• Rick Savage
• Josh Smith
• David Tanner
• Luke Williams

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Extras
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Old Faraday Isolator
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Old Faraday Isolator