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In this thesis, ultimate sensitive measurement forweak force imposed on a suspended mirror is performed with the help of a laserand an optical cavity for the development of gravitational-wave detectors.According to the Heisenberg uncertainty principle, such measurements aresubject to a fundamental noise called quantum noise, which arises from thequantum nature of a probe (light) and a measured object (mirror). One of thesources of quantum noise is the quantum back-action, which arises from thevacuum fluctuation of the light. It sways the mirror via the momentumtransferred to the mirror upon its reflection for the measurement. The authordiscusses a fundamental trade-off between sensitivity and stability in themacroscopic system, and suggests using a triangular cavity that can avoid thistrade-off. The development of an optical triangular cavity is described and itscharacterization of the optomechanical effect in the triangular cavity isdemonstrated. As a result, for the first time in the world the quantum back-actionimposed on the 5-mg suspended mirror is significantly evaluated. This workcontributes to overcoming the standard quantum limit in the future.
List of contents
Introduction.- Theory of Optomechanics.- Application of Optomechanics.- Optical Torsional Spring.- Experimental Setup.- Experimental Results.- The Future.- Conclusions.
About the author
Dr.Nobuyuki Matsumoto
The university of Tokyo, Physics Department
matsumoto@granite.phys.s.u-tokyo.ac.jp
Summary
In this thesis, ultimate sensitive measurement for
weak force imposed on a suspended mirror is performed with the help of a laser
and an optical cavity for the development of gravitational-wave detectors.
According to the Heisenberg uncertainty principle, such measurements are
subject to a fundamental noise called quantum noise, which arises from the
quantum nature of a probe (light) and a measured object (mirror). One of the
sources of quantum noise is the quantum back-action, which arises from the
vacuum fluctuation of the light. It sways the mirror via the momentum
transferred to the mirror upon its reflection for the measurement. The author
discusses a fundamental trade-off between sensitivity and stability in the
macroscopic system, and suggests using a triangular cavity that can avoid this
trade-off. The development of an optical triangular cavity is described and its
characterization of the optomechanical effect in the triangular cavity is
demonstrated. As a result, for the first time in the world the quantum back-action
imposed on the 5-mg suspended mirror is significantly evaluated. This work
contributes to overcoming the standard quantum limit in the future.
