Würzburg 2018 – scientific programme
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GR: Fachverband Gravitation und Relativitätstheorie
GR 4: Gravitational waves II
GR 4.2: Talk
Tuesday, March 20, 2018, 16:50–17:10, Phys-SR-SE1
Enhancing the Optical Spring in Gravitational-Wave Detectors via Intra-Cavity Optical-Parametric Amplification — •Mikhail Korobko1, Farid Ya. Khalili2,3, and Roman Schnabel1 — 1Institut für Laserphysik und Zentrum für Optische Quantentechnologien, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany — 2Moscow State University, Department of Physics, Moscow 119992, Russia — 3Russian Quantum Center, Skolkovo 143025, Russia
Over the past two years Advanced LIGO and Advanced Virgo gravitational wave detectors have made several observations of gravitational waves from merging binary black holes and binary neutron stars. Extending the detection range and increasing the number of events requires a higher sensitivity of the detectors, that is mainly limited by the quantum radiation pressure and shot noise in the current design. One of the ways to improve the sensitivity is to use the optical spring effect, where detuning the optical cavity from its resonance causes the electromagnetic fluctuations to create a position-dependent force on the detector mirrors. This additional force gives a rise to a resonant enhancement in sensitivity for some gravitational wave frequency. We investigate the use of an optical parametric amplification to enhance this effect. We discuss how the frequency of this resonance can be tuned dynamically, matching the signal frequency of a signal, thus achieving a significant and broadband enhancement in sensitivity. We show that this all-optical control of the optical spring can be a versatile way of shaping the sensitivity in future gravitational-wave detectors.