Laserfrequencymodulated Sagnac interferometry for sensitive saturation spectroscopy

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Laser-frequency-modulated Sagnac interferometry
for sensitive saturation spectroscopy
Glenn de Vine, Matthieu Vangeleyn, Alain
Brillet, C. Nary Man David McClelland, Malcolm
Gray (ANU, Australia)
Observatoire de la Côte d'Azur Département
ARTEMIS NICE glenn_at_oca.eu
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Talk Outline

• Sagnac interferometer basics
• Sagnac interferometer for noise-rejection
• The 3rd harmonic technique
• The tilt-locking technique
• Experimental results
• Summary

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Sagnac Interferometry
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Sagnac saturated absorptionspectroscopy
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3rd Harmonic Sagnac Spectroscopy
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Harmonic signals
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Tilt-locking1 Sagnac spectroscopy
1. D. A. Shaddock, M. B. Gray and D. E.
McLelland, Opt. Lett., 24, 1999
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Tilt-locking spectroscopy 101
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Modulation-free, hyperfine error signals
Caesium at 852nm
N. Robins, B. Slagmolen, D. Shaddock, M. Gray, J.
Close, Optics Letters 27, 1905 (2002).
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DC Signal to Noise Ratio for Iodine at 532nm
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Beam Pointing Noise
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2nd Harmonic, Tilt-locking Technique
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Frequency Stability Results
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Applications for LISA

• Laser frequency stabilisation (not likely)
• Initial phase-locking of LISA lasers
• Possibly us Cs2 at 1064 nm

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Summary

• compact
• relatively simple
• low power consumption - no RF electronics
• cheap - no RF electronics
• RF modulation with an EOM would enable the
  possibility for shot-noise-limited measurements