We demonstrate the possibility of surpassing the quantum noise limit for simultaneous multi-axis spatial displacement measurements that have zero mean values. The requisite resources for these measurements are squeezed light beams with exotic transverse mode profiles. We show that, in principle, lossless combination of these modes can be achieved using the non-degenerate Gouy phase shift of optical resonators. When the combined squeezed beams are measured with quadrant detectors, we experimentally demonstrate a simultaneous reduction in the transverse x- and y- displacement fluctuations of 2.2 dB and 3.1 dB below the quantum noise limit.
@article{arxiv.quant-ph/0311122,
title = {Nano-displacement measurements using spatially multimode squeezed light},
author = {N. Treps and N. Grosse and W. P. Bowen and M. T. L. Hsu and A. Maitre and C. Fabre and H. -A. Bachor and P. K. Lam},
journal= {arXiv preprint arXiv:quant-ph/0311122},
year = {2009}
}
Comments
21 pages, 9 figures, submitted to "Special Issue on Fluctuations & Noise in Photonics & Quantum Optics" of J. Opt. B