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arXiv · 1109.3731

Long-term stable squeezed vacuum state of light for gravitational wave detectors

Alexander Khalaidovski·Henning Vahlbruch·Nico Lastzka·Christian Graef·Karsten Danzmann·Hartmut Grote·Roman Schnabel
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Abstract

Currently, the German/British gravitational wave detector GEO600 is being upgraded in course of the GEO-HF program. One part of this upgrade consists of the integration of a squeezed light laser to nonclassically improve the detection sensitivity at frequencies where the instrument is limited by shot noise. This has been achieved recently [1]. The permanent employment of squeezed light in gravitational wave observatories requires a long-term stability of the generated squeezed state. In this paper, we discuss an unwanted mechanism that can lead to a varying squeezing factor along with a changing phase of the squeezed field. We present an extension of the implemented coherent control scheme [2] that allowed an increase in the long-term stability of the GEO600 squeezed light laser. With it, a quantum noise reduction by more than 9 dB in the frequency band of 10 Hz - 10 kHz was observed over up to 20 hours with a duty cycle of more than 99%.

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Alexander Khalaidovski, Henning Vahlbruch, Nico Lastzka, Christian Graef, Karsten Danzmann, Hartmut Grote, Roman Schnabel. 2011-09-16. Long-term stable squeezed vacuum state of light for gravitational wave detectors. https://doi.org/10.1088/0264-9381%2F29%2F7%2F075001

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