LIGO Document P080111-x0

Picometer level displacement metrology with digitally enhanced heterodyne interferometry

Document #:
LIGO-P080111-x0
Document type:
P - Publications
Abstract:
Digitally enhanced heterodyne interferometry is a laser metrology technique employing pseudo-random codes phase modulated onto an optical carrier. We present the first characterization of the technique’s displacement sensitivity. The displacement of an optical cavity was measured using digitally enhanced heterodyne interferometry and compared to a simultaneous readout based on conventional Pound-Drever-Hall locking. The techniques agreed to within 5 pm/√Hz at 1 Hz, providing an upper bound to the displacement noise of digitally enhanced heterodyne interferometry. These measurements employed a real-time signal extraction system implemented on a field programmable gate array, suitable for closed-loop control applications. We discuss the applicability of digitally enhanced heterodyne interferometry for lock acquisition of advanced gravitational wave detectors.
Files in Document:
Notes and Changes:

Rev P080111-00-Z:
- Full document number: LIGO-P080111-00-Z
- Author(s): Glenn De Vine; D.s. Rabeling; Bram Slagmolen; Timothy Lam
- Document date: 2008-11-26
- Document received date: 2008-11-26
- Document entry date: 2008-11-26

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