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Free keywords:
Quantum Physics, quant-ph, Physics, Optics, physics.optics
Abstract:
Conventional heterodyne readout schemes are now under reconsideration due to
the realization of techniques to evade its inherent 3 dB signal-to-noise
penalty. The application of high-frequency, spectrally entangled, two-mode
squeezed states can further improve the readout sensitivity of audio-band
signals. In this paper, we experimentally demonstrate quantum-enhanced
heterodyne readout of two spatially distinct interferometers with direct
optical signal combination, circumventing the 3 dB heterodyne signal-to-noise
penalty. Applying a high-frequency, spectrally entangled, two-mode squeezed
state, we show further signal-to-noise improvement of an injected audio band
signal of 3.5 dB. This technique is applicable for quantum-limited
high-precision experiments, with application to searches for quantum gravity,
gravitational wave detection and wavelength-multiplexed quantum communication.
