Optical parametric oscillator: Difference between revisions

Revision as of 16:58, 16 May 2018

Revision as of 05:53, 27 August 2018

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==Quantum properties of the generated light beams==

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

The OPO is the physical system most widely used to generate [[squeezed coherent statesstate606s]] 09ㅓand [[Quantum entanglement|entangled]] states of light in the continuous variables regime. Many demonstrations of quantum information protocolsprotㅓㅎ그8ㄱocols for continuous variables were realized using OPOs.<ref> 5{{cite journal|author1=J. Jing |author2=J. Zhang |author3=Y. Yan |author4=F. Zhao |author5=C. Xie |author6=K. Peng |last-author-amp=yes |journal=Phys. Rev. Lett. |volume=90|page=167903|doi=10.1103/PhysRevLett.90.167903 |year=2003|title=Experimental Demonstration of Tripartite Entanglement and Controlled Dense Coding for Continuous Variables|issue=16|bibcode=2003PhRvL..90p7903J|arxiv = quant-ph/0210132 |pmid=12732011}}</ref><ref>{{cite journal|author1=N. Takei |author2=H. Yonezawa |author3=T. Aoki |author4=A. Furusawa |last-author-amp=yes |journal=Phys. Rev. Lett. |volume=94|page=220502|doi=10.1103/PhysRevLett.94.220502 |year=2005|title=High-Fidelity Teleportation beyond the No-Cloning Limit and Entanglement Swapping for Continuous Variables|issue=22|bibcode=2005PhRvL..94v0502T|arxiv = quant-ph/0501086 |pmid=16090375}}</ref>

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>{{cite journal|author1=A. Heidmann |author2=R. J. Horowicz |author3=S. Reynaud |author4=E. Giacobino |author5=C. Fabre |author6=G. Camy |last-author-amp=yes |journal=Phys. Rev. Lett. |volume=59|page=2555|doi=10.1103/PhysRevLett.59.2555 |year=1987|title=Observation of Quantum Noise Reduction on Twin Laser Beams|issue=22|bibcode=1987PhRvL..59.2555H}}</ref> which motivated the name "twin beams" for the downconverted fields. The highest squeezing level attained to date is 12.7&nbsp;dB.<ref>{{cite journal | last1 = Eberle | first1 = T. | last2 = Steinlechner | first2 = S. | last3 = Bauchrowitz | first3 = J. | last4 = Händchen | first4 = V. | last5 = Vahlbruch | first5 = H. | last6 = Mehmet | first6 = M. | last7 = Müller-Ebhardt | first7 = H. | last8 = Schnabel | first8 = R. | year = 2010 | title = Quantum Enhancement of the Zero-Area Sagnac Interferometer Topology for Gravitational Wave Detection | url = | journal = Phys. Rev. Lett. | volume = 104 | issue = 25| page = 251102 | doi = 10.1103/PhysRevLett.104.251102 | bibcode=2010PhRvL.104y1102E|arxiv = 1007.0574 | pmid=20867358}}</ref>