Fabrication and measurement of optics for the Laser Interferometer Gravitational Wave Observatory

Walsh, Christopher J.; Leistner, Achim J.; Seckold, Jeffrey A.; Oreb, Bozenko F.; Farrant, David I.

doi:10.1364/ao.38.002870

Cited by 24 publications

(12 citation statements)

References 12 publications

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“…The profilometer was calibrated with an optical flat [5] placed on the upper frame. The calibration flat was independently measured to have a sag of 4.4 nm across its surface and a roughness of 2 nm RMS in the spatial frequency range from full diameter to ~ 1/mm.…”

Section: Focal Plane Co-planaritymentioning

confidence: 99%

The 12K×8K CCD mosaic camera for the Palomar Transient Factory

et al. 2008

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The Palomar Transient Factory is an automated wide-field survey facility dedicated to identifying a wide range of transient phenomena. Typically, a new 7.5 square degree field will be acquired every 90 seconds with 66% observing efficiency, in g' band when the sky is dark, or in R band when the moon is up. An imaging camera with a 12Kx8K mosaic of MIT/LL CCDs, acquired from CFHT, is being repackaged to fit in the prime focus mounting hub of the Palomar 48-inch Oschin Schmidt Telescope. We discuss how we have addressed the broad range of issues presented by this application: faster CCD readout to improve observing efficiency, a new cooling system to fit within the constrained space, a low impact shutter to maintain reliability at the fast observing cadence, a new filter exchange mechanism, and the field flattener needed to correct for focal plane curvature. The most critical issue was the tight focal plane alignment and co-planarity requirements created by the fast beam and coarse plate scale. We built an optical profilometer system to measure CCDs heights and tilts with 1 µm RMS accuracy.

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Section: Focal Plane Co-planaritymentioning

confidence: 99%

The 12K×8K CCD mosaic camera for the Palomar Transient Factory

et al. 2008

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“…The main interferometer optics [19,20] are fabricated from high-purity fused silica, 25 cm in diameter and 10 cm thick (except the beamsplitter which is 4 cm thick). Radii of curvature of the cavity optics are chosen so that the arm cavities have a stability g ¼ ð1 À L=R 1 Þð1 À L=R 2 Þ (L is the cavity length and R n are the radii of curvature of the two cavity mirrors) of 0.33 (H1 and L1) or 0.67 (H2), to minimize the excitation of higher order transverse modes by separating them in frequency from the laser frequency and its RF modulation sidebands.…”

Section: Interferometer Opticsmentioning

confidence: 99%

“…19 Currently at Mission Research Corporation. 20 Currently at Harvard University. 21 Currently at Lockheed-Martin Corporation.…”

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confidence: 99%

Detector description and performance for the first coincidence observations between LIGO and GEO

Abbott

Adhikari

et al. 2004

Nuclear Instruments and Methods in Physics Research Section A:

276

161

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For 17 days in August and September 2002, the LIGO and GEO interferometer gravitational wave detectors were operated in coincidence to produce their first data for scientific analysis. Although the detectors were still far from their design sensitivity levels, the data can be used to place better upper limits on the flux of gravitational waves incident on the earth than previous direct measurements. This paper describes the instruments and the data in some detail, as a companion to analysis papers based on the first data. r

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“…This also implies that we can assume all beams and cavity modes strictly Gaussian, their transverse edge not being determined by finite aperture effects. We engage optical elements of highest quality and precision [2].…”

Section: Introductionmentioning

confidence: 99%

Carrier mode selective working point and side band imbalance in LIGO I

D’Ambrosio

Kells

2006

Phys. Rev. D

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In gravitational wave interferometers, the input laser beam is phase modulated to generate radiofrequency side bands that are used to lock the cavities. The mechanism is the following: the frequency of the side bands and the carrier is chosen in such a way that their response to small changes of the longitudinal degrees of freedom is different. This difference is therefore monitored and it serves as an error signal for controlling the optical cavity lengths, as they are linearly related to the set of observed phases between carrier and side bands. Among the others, one longitudinal degree of freedom is optimally sensitive to the space-time distortions propagating through the cosmos, as predicted by the general theory of relativity. The observation of the astrophysical signal relies on the measurement of that specific degree of freedom. The entire problem is more complex when the transverse degrees of freedom are taken into account, because the relative phase between the fields also depends on their overlap. In order to establish an unambiguous relation between length changes and phase measurements, there must be one circulating optical mode and the only difference between carrier and side bands must be their amplitude. We will show that the variability of the transverse degrees of freedom and their different actions on carrier and side band fields puts a severe limit on this assumption. Unless the system is made of perfect and perfectly matched optical cavities, it is never governed by one unique coherent state and any adjustment of the optical lengths results from a compromise between the lengths that are optimal for the carrier field and the side band ones. Such a compromise alters the correspondence between error signals and cavity lengths, calculated in the one-dimensional treatment. We assess the strength of this effect and relate it to the sensitivity of the instrument (which relies on the reconstruction of that correspondence) in realistic circumstances.

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Fabrication and measurement of optics for the Laser Interferometer Gravitational Wave Observatory

Cited by 24 publications

References 12 publications

The 12K×8K CCD mosaic camera for the Palomar Transient Factory

The 12K×8K CCD mosaic camera for the Palomar Transient Factory

Detector description and performance for the first coincidence observations between LIGO and GEO

Carrier mode selective working point and side band imbalance in LIGO I

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