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arXiv:1505.03903 · Physical Review A

Full quantum state reconstruction of symmetric two-mode squeezed thermal states via spectral homodyne detection and a state-balancing detector

S. Cialdi, Carmen Porto, Daniele Cipriani, Stefano Olivares, Matteo G. A. Paris

Published Apr 5, 2016• 20 citations
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Abstract

We suggest and demonstrate a scheme to reconstruct the symmetric two-mode squeezed thermal states of spectral sideband modes from an optical parametric oscillator. The method is based on both a single homodyne detector and the error signal from the active stabilization of the oscillator cavity. The measurement scheme has been successfully tested on different two-mode squeezed thermal states, ranging from uncorrelated coherent states to entangled states.

DOI
10.1103/physreva.93.043805

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The quantum noise in photocurrent fluctuations usually gives incomplete information about the quantum state of spectral sideband modes of bright light beams involved in the detection. Each frequency component of the noise spectrum corresponds to two sideband modes symmetrically located around the bright optical field. In the case of the usual homodyne detection, it limits the ability to recover discriminated information of each mode involved. We theoretically show that complete reconstruction of the two-mode quantum state can be obtained by using phase-locked (coherent) resonator detection, even for non-Gaussian states. We experimentally demonstrate the technique by measuring a two-mode displaced coherent state.