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arXiv · 1908.05914

Design and experimental demonstration of a laser modulation system for future gravitational-wave detectors

Kohei Yamamoto·Keiko Kokeyama·Yuta Michimura·Yutaro Enomoto·Masayuki Nakano·Gui-Guo Ge·Tomoyuki Uehara·Kentaro Somiya·Kiwamu Izumi·Osamu Miyakawa·Takahiro Yamamoto·Takaaki Yokozawa·Yuta Fujikawa·Nobuyuki Fujii·Takaaki Kajita
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Abstract

Detuning the signal-recycling cavity length from a cavity resonance significantly improves the quantum noise beyond the standard quantum limit, while there is no km-scale gravitational-wave detector successfully implemented the technique. The detuning technique is known to introduce great excess noise, and such noise can be reduced by a laser modulation system with two Mach-Zehnder interferometers in series. This modulation system, termed Mach-Zehnder Modulator (MZM), also makes the control of the gravitational-wave detector more robust by introducing the third modulation field which is non-resonant in any part of the main interferometer. On the other hand, mirror displacements of the Mach-Zehnder interferometers arise a new kind of noise source coupled to the gravitational-wave signal port. In this paper, the displacement noise requirement of the MZM is derived, and also results of our proof-of-principle experiment is reported.

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Kohei Yamamoto, Keiko Kokeyama, Yuta Michimura, Yutaro Enomoto, Masayuki Nakano, Gui-Guo Ge, Tomoyuki Uehara, Kentaro Somiya, Kiwamu Izumi, Osamu Miyakawa, Takahiro Yamamoto, Takaaki Yokozawa, Yuta Fujikawa, Nobuyuki Fujii, Takaaki Kajita. 2019-08-16. Design and experimental demonstration of a laser modulation system for future gravitational-wave detectors. https://doi.org/10.1088/1361-6382%2Fab4489

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