Time Delay Interferometry at UF
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The main problem of any experimental verification of TDI is the time delay itself. Optical delay lines in the lab will never reach 16s time delays. Our group is developing a technique, which utilizes an electronic delay to generate a LISA-like signal within an optical set-up. |
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Laser 0 (the reference laser) transfers the frequency noise of Laser 1 into the RF or audio band RF or audio signal will be digitized, delayed, and then regenerated at Laser 2. Laser 0 transfers Laser 2 frequency noise into the RF or audio band Demodulate S2 with time-delayed S1 Signal |
The Demodulated signal can be used to phase lock the local laser, this is called transponder or arm locking. The Demodulated signal can be used to form TDI-type linear combinations to cancel the laser frequency noise, as shown in the left-hand column. |
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Generating LISA-like signals for Time Delay Interferometry The phase noise in this signal is a linear combination
of the time-delayed phase noises of the far laser (Laser
1) and the reference laser (Laser 0)
and of the actual phase noises of the local laser (Laser
2) and the reference laser. Important for us is the fact that
the noise of our signal has the same characteristic of the noise of the
LISA signal. Linear combinations similar to the ones derived for TDI
cancel the laser frequency noise. |
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Our first experimental goal is a LISA-like interferometer
with one laser representing each S/C. It can be used to verify TDI in
all possible configurations. We will be able to also study timing problems
and demonstrate arm locking. One additional laser per S/C can be added to generate a complete LISA-like interferometer. |
A full experimental verification
of all phase meter and control loops is also part of our program. |
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| For more information refer to... Publications: James Ira Thorpe et al, "First step toward a benchtop model of the Laser Interferometer Space Antenna" 2004 Optics Letters, Vol. 29, Issue 24, pp. 2843 doi:10.1364/OL.29.002843 James Ira Thorpe et al, "Electronic phase delay; a first step towards a bench-top model of LISA" 2005 Class. Quantum Grav. 22 S227 doi:10.1088/0264-9381/22/10/014 Rachel J Cruz et al, "The LISA benchtop simulator at the University of Florida" 2006 Class. Quantum Grav. 23 S751 doi:10.1088/0264-9381/23/19/S14 Shawn J Mitryk et al, "Verification of time-delay interferometry techniques using the University of Florida LISA interferometry simulator" 2010 Class. Quantum Grav. 27 084012 doi:10.1088/0264-9381/27/8/084012 Shawn J Mitryk et al, "Demonstration of Time Delay Interferometry and Spacecraft Ranging in a Space-based Gravitational Wave Detector using the UF-LISA Interferometry Simulator" 2012, arXiv:1205.1934 [astro-ph.IM] Dissertations: Rachel J. Cruz DEVELOPMENT OF THE UF LISA BENCHTOP SIMULATOR FOR TIME DELAY INTERFEROMETRY Shawn Mitryk LASER NOISE MITIGATION THROUGH TIME DELAY INTERFEROMETRY FOR SPACE-BASED GRAVITATIONAL WAVE INTERFEROMETERS USING THE UF LASER INTERFEROMETRY SIMULATOR |