Quantum enhancement of the zero-area Sagnac interferometer topology for gravitational wave detection.

Only a few years ago, it was realized that the zero-area Sagnac interferometer topology is able to perform quantum nondemolition measurements of position changes of a mechanical oscillator. Here, we experimentally show that such an interferometer can also be efficiently enhanced by squeezed light. We achieved a nonclassical sensitivity improvement of up to 8.2 dB, limited by optical loss inside our interferometer. Measurements performed directly on our squeezed-light laser output revealed squeezing of 12.7 dB. We show that the sensitivity of a squeezed-light enhanced Sagnac interferometer can surpass the standard quantum limit for a broad spectrum of signal frequencies without the need for filter cavities as required for Michelson interferometers. The Sagnac topology is therefore a powerful option for future gravitational-wave detectors, such as the Einstein Telescope, whose design is currently being studied.

[1]  Keisuke Goda,et al.  A quantum-enhanced prototype gravitational-wave detector , 2008, 0802.4118.

[2]  Karsten Danzmann,et al.  Observation of squeezed states with strong photon-number oscillations , 2009, 0909.5386.

[3]  Kirk McKenzie,et al.  Experimental demonstration of a squeezing-enhanced power-recycled michelson interferometer for gravitational wave detection. , 2002, Physical review letters.

[4]  Bernard F. Schutz,et al.  The GEO 600 gravitational wave detector , 2002 .

[5]  Karsten Danzmann,et al.  Demonstration of a squeezed-light-enhanced power- and signal-recycled Michelson interferometer. , 2005, Physical review letters.

[6]  C. Caves.  Quantum Mechanical Noise in an Interferometer , 1981 .

[7]  D. McClelland,et al.  Experimental demonstration of resonant sideband extraction in a sagnac interferometer. , 1998, Applied optics.

[8]  Karsten Danzmann,et al.  Observation of squeezed light with 10-dB quantum-noise reduction. , 2007, Physical review letters.

[9]  Hidehiro Yonezawa,et al.  Observation of -9 dB quadrature squeezing with improvement of phase stability in homodyne measurement. , 2007, Optics express.

[10]  Andrew G. Glen,et al.  APPL , 2001 .

[11]  Yanbei Chen.  Sagnac interferometer as a speed-meter-type, quantum-nondemolition gravitational-wave detector , 2003 .

[12]  Gustafson,et al.  Sagnac interferometer for gravitational-wave detection. , 1996, Physical review letters.

[13]  R. Loudon.  Quantum Optics, Experimental Gravitation, and Measurement Theory , 1984 .

[14]  R. Schnabel,et al.  Quantum engineering of squeezed states for quantum communication and metrology , 2007, 0707.2845.

[15]  Stable operation of a 300-m laser interferometer with sufficient sensitivity to detect gravitational-wave events within our galaxy. , 2001, Physical review letters.

[16]  et al,et al.  Detector description and performance for the first coincidence observations between LIGO and GEO , 2004 .

[17]  W. Del Pozzo,et al.  Triple Michelson interferometer for a third-generation gravitational wave detector , 2008, 0804.1036.

[18]  B. J. Meers,et al.  Recycling in laser-interferometric gravitational-wave detectors. , 1988, Physical review. D, Particles and fields.

[19]  D. Kracht,et al.  Nd:YAG ring laser with 213 W linearly polarized fundamental mode output power. , 2005, Optics express.

[20]  R. Krotkov,et al.  Quantum Optics, Experimental Gravitation, and Measurement Theory , 1983 .

[21]  Andrey B. Matsko,et al.  Conversion of conventional gravitational-wave interferometers into quantum nondemolition interferometers by modifying their input and/or output optics , 2001 .