A source of illumination for low-noise 'Violin-Mode' shadow sensors, intended for use in interferometric gravitational wave detectors

Nicholas Lockerbie, Kirill Tokmakov, K. A. Strain

Research output: Contribution to journalArticle

4 Citations (Scopus)

Abstract

A low-noise source of illumination is described for shadow-sensors having a displacement sensitivity of (69 ± 13) picometres (rms)/√Hz, at 500 Hz, over a measuring span of ±0.1 mm. These sensors were designed to detect ‘Violin-Mode’ resonances in the suspension fibres of the test-masses/mirrors for the Advanced LIGO (Laser Interferometer Gravitational wave Observatory) gravitational wave detectors. The source of illumination (emitter) described here used a single column of 8 × miniature Near InfraRed LEDs (λ = 890 nm). These emitters cast the shadows of 400 µm diameter fused silica suspension fibres onto their complementary shadow-displacement detectors, located at a distance of 74 fibre diameters (29.6 mm) behind the axes of the fibres themselves. Violin-Mode vibrations of each fibre were sensed as differential AC photocurrents in the corresponding ‘split-photodiode’ detector. This paper describes the design, construction, noise analysis, and measures that were taken in the conception of the emitters, in order to produce high-contrast shadows at such distant detectors. In this way it proved possible to obtain, simultaneously, a very high transfer sensitivity to Violin-Mode vibration of the fibres, and a very low level of detection noise—close to the fundamental shot noise limit—whilst remaining within the constraints of this simple design of emitter. The shadow detector is described in an accompanying paper.
LanguageEnglish
Article number125111
Number of pages12
JournalMeasurement Science and Technology
Volume25
Issue number12
DOIs
Publication statusPublished - 7 Nov 2014

Fingerprint

Gravity waves
Gravitational Waves
gravitational waves
low noise
Illumination
Lighting
illumination
Detector
Detectors
Sensor
Fiber Suspension
fibers
Fibers
Fiber
sensors
detectors
Sensors
emitters
Light sources
vibration mode

Keywords

  • LED arrays
  • shadow displacement sensors
  • gravitational wave detectors

Cite this

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title = "A source of illumination for low-noise 'Violin-Mode' shadow sensors, intended for use in interferometric gravitational wave detectors",
abstract = "A low-noise source of illumination is described for shadow-sensors having a displacement sensitivity of (69 ± 13) picometres (rms)/√Hz, at 500 Hz, over a measuring span of ±0.1 mm. These sensors were designed to detect ‘Violin-Mode’ resonances in the suspension fibres of the test-masses/mirrors for the Advanced LIGO (Laser Interferometer Gravitational wave Observatory) gravitational wave detectors. The source of illumination (emitter) described here used a single column of 8 × miniature Near InfraRed LEDs (λ = 890 nm). These emitters cast the shadows of 400 µm diameter fused silica suspension fibres onto their complementary shadow-displacement detectors, located at a distance of 74 fibre diameters (29.6 mm) behind the axes of the fibres themselves. Violin-Mode vibrations of each fibre were sensed as differential AC photocurrents in the corresponding ‘split-photodiode’ detector. This paper describes the design, construction, noise analysis, and measures that were taken in the conception of the emitters, in order to produce high-contrast shadows at such distant detectors. In this way it proved possible to obtain, simultaneously, a very high transfer sensitivity to Violin-Mode vibration of the fibres, and a very low level of detection noise—close to the fundamental shot noise limit—whilst remaining within the constraints of this simple design of emitter. The shadow detector is described in an accompanying paper.",
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A source of illumination for low-noise 'Violin-Mode' shadow sensors, intended for use in interferometric gravitational wave detectors. / Lockerbie, Nicholas; Tokmakov, Kirill; Strain, K. A.

In: Measurement Science and Technology, Vol. 25, No. 12, 125111, 07.11.2014.

Research output: Contribution to journalArticle

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T1 - A source of illumination for low-noise 'Violin-Mode' shadow sensors, intended for use in interferometric gravitational wave detectors

AU - Lockerbie, Nicholas

AU - Tokmakov, Kirill

AU - Strain, K. A.

N1 - Dat of Acceptance: 07/10/2014

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