Optical parametric oscillator: Difference between revisions

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Revision as of 13:42, 24 March 2011

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== Quantum properties of the generated light beams ==

[[Image:OPO Crystals.jpg‎‎|thumb|300 px|right|[[Potassium titanyl phosphate|KTP]] crystals in an OPO]]

The OPO is the physical system most widely used to generate [[squeezed coherent states]] and [[entangled]] states of light in the continuous variables regime. Many demonstrations of quantum information protocols for continuous variables were realized using OPO'sOPOs.<ref>J. Jing, J. Zhang, Y. Yan, F. Zhao, C. Xie, and K. Peng, Phys. Rev. Lett. '''90''', 167903 (2003).</ref><ref name="Koike">S. Koike, H. Takahashi, H. Yonezawa, N. Takei, S. L. Braunstein, T. Aoki, and A. Furusawa, Phys. Rev. Lett. '''96''', 060504 (2006).</ref><ref>N. Takei, H. Yonezawa, T. Aoki, and A. Furusawa, Phys. Rev. Lett. '''94''', 220502 (2005).</ref><ref name="Koike" />

The [[Spontaneous parametric down conversion|downconversion]] process really occurs in the single photon regime: each pump photon that is annihilated inside the cavity gives rise to a pair of photons in the signal and idler intracavity modes. This leads to a quantum correlation between the intensities of signal and idler fields, so that there is squeezing in the subtraction of intensities,<ref>A. Heidmann, R. J. Horowicz, S. Reynaud, E. Giacobino, C. Fabre, and G. Camy, Phys. Rev. Lett. '''59''', 2555 (1987).</ref> which motivated the name "twin beams" for the downconverted fields. The highest squeezing level attained was 10.12 +/- 0.15 dB.<ref>Schnabel et al., Phys. Rev. Lett. '''100''', 033602 (2008).</ref>