• LCGT
• AIC
• QND

QND

Members

• Seiji Karamura
• Koji Nagano
• Yutaro Enomoto
• Yuzuru Sakai
• Masayuki Nakano

Research advisor

• Akira Furusawa

Overview

The aim of this experiment is demonstrating in lab scale the technique of the quantum radiation pressure noise (QRPN) reduction by measuring the ponderomotively squeezed light with the homodyne detector. With this technique, the sensitivity of KAGRA can beat the standard quantum limit.

In order to demonstrate the QRPN reduction technique, the sensitivity limited by QRPN should be achieved. In this experiment, in order to enhance QRPN, it is planed to use the high finesse (~10⁴) cavity consisting of 23-mg tiny mirror and ~50-g 2.54-cm mirror. Using this cavity (x2), Fabry--Perot Michelson interferometer will be construed to reduce the noise other than QRPN. As a result, the QRPN in this experiment is expected to be 10⁴ times larger than that in KAGRA in therms of displacement noise (m/rtHz) although the laser light source with ~200 mW output power is used in this experiment.

Current status

This experiment is temporarily suspended now (2017/02/16) for lab moving. The status before the lab moving is summarized in the related paper [12]. The 23 mg mirrors are kept in the desiccator in the ICRR B1 Lab and will be moved to Ando Lab (UT).

Related papers

1. S. Sakata, S. Kawamura, S. Sato, K. Somiya, K. Arai, M. Fukushima, A. Sugamoto, Development of a control scheme of homodyne detection for extracting ponderomotive squeezing from a Michelson interferometer, J. Phys. Conf. Ser. 32 (2006).

2. S. Sakata, Study of the Reduction of the Radiation Pressure Noise in Gravitational Wave Detectors using the Ponderomotive Squeezing, PhD thesis, Ochanomizu University (2008)

3. S. Sakata, O. Miyakawa, A. Nishizawa, H. Ishizaki, S. Kawamura, Measurement of angular antispring effect in optical cavity by radiation pressure, Phys. Rev. D 81 (2010)

4. T. Mori, Development of a high power optical cavity for optomechanical quantum nondemolition measurement, PhD thesis, The University of Tokyo (2011)
5. M. Nakano, Study of Opt-Mechanical Cavity Control for Development of Quantum Noise Reduction in KAGRA Gravitational Wave Detector, Master thesis, The University of Tokyo (2014)
6. S. Konisho, Study of the mirror angular control for optimization of quantum noise in a gravitational wave detector, Master thesis, The University of Tokyo (2015)
7. T. Nishimura, Design and development of the vibration isolation system for studying radiation pressure noise reduction in a gravitational wave detector, Master thesis, The University of Tokyo (2015)

8. K. Nagano, Y. Enomoto, M. Nakano, A. Furusawa, S. Kawamura, New method to measure the angular antispring effect in a Fabry–Perot cavity with remote excitation using radiation pressure, Phys. Lett. A 380 (2016)

9. Y. Enomoto, K. Nagano, M. Nakano, A. Furusawa, S. Kawamura, Observation of reduction of radiation-pressure-induced rotational anti-spring effect on a 23 mg mirror in a Fabry–Perot cavity, Class. Quantum Gravity 33 (2016)

10. K. Nagano, Y. Enomoto, M. Nakano, A. Furusawa, S. Kawamura, Mitigation of radiation-pressure-induced angular instability of a Fabry–Perot cavity consisting of suspended mirrors, Phys. Lett. A 380 (2016)

11. Y. Enomoto, On optomechanical interactions in interferometric gravitational wave detectors and fluctuations of spatial modes of light, Master thesis, The University of Tokyo (2017)

12. K. Nagano, A study on the reduction of quantum noise for the gravitational wave detector KAGRA, Master thesis, The University of Tokyo (2017)