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arXiv · 1703.02179

Sensitivity Characterisation of a Parametric Transducer for Gravitational Wave Detection Through Optical Spring Effect

N. C. Carvalho·O. D. Aguiar·J. Bourhill·M. E. Tobar
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Abstract

We present the characterisation of the most recent parametric transducers designed to enhance the Mario Schenberg Gravitational Wave Detector sensitivity. The transducer is composed of a microwave re-entrant cavity that attaches to the gravitational wave antenna via a rigid spring. It functions as a three-mode mass-spring system; motion of the spherical antenna couples to a 50 $μm$ thick membrane, which converts its mechanical motion into a frequency shift of the cavity resonance. Through the optical spring effect, the microwave transducer frequency-displacement sensitivity was measured to be 726 $MHz/μ$m at 4 K. The spherical antenna detection sensitivity is determined analytically using the transducer amplification gain and equivalent displacement noise in the test setup, which are 5.5 $\times$ 10$^{11} V/m$ and $1.8 \times 10^{-19} m\sqrt{Hz}^{-1}$, respectively.

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N. C. Carvalho, O. D. Aguiar, J. Bourhill, M. E. Tobar. 2017-07-24. Sensitivity Characterisation of a Parametric Transducer for Gravitational Wave Detection Through Optical Spring Effect. https://doi.org/10.1088/1361-6382%2Faa7fff

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