Biphoton generation in quadratic waveguide arrays: A classical optical simulation

Quantum entanglement became essential in understanding the non-locality of quantum mechanics. In optics, this non-locality can be demonstrated on impressively large length scales, as photons travel with the speed of light and interact only weakly with their environment. Spontaneous parametric down-conversion (SPDC) in nonlinear crystals provides an efficient source for entangled photon pairs, so-called biphotons. However, SPDC can also be implemented in nonlinear arrays of evanescently coupled waveguides which allows the generation and the investigation of correlated quantum walks of such biphotons in an integrated device. Here, we analytically and experimentally demonstrate that the biphoton degrees of freedom are entailed in an additional dimension, therefore the SPDC and the subsequent quantum random walk in one-dimensional arrays can be simulated through classical optical beam propagation in a two-dimensional photonic lattice. Thereby, the output intensity images directly represent the biphoton correlations and exhibit a clear violation of a Bell-like inequality.

[1]  W. Marsden.  I and J , 2012 .

[2]  J. Bell.  On the Einstein-Podolsky-Rosen paradox , 1964 .

[3]  S. Longhi.  Quantum‐optical analogies using photonic structures , 2009 .

[4]  Roberto Morandotti,et al.  Quantum and classical correlations in waveguide lattices. , 2008, Physical review letters.

[5]  Yanhua Shih.  An Introduction to Quantum Optics , 2011 .

[6]  F. Martini,et al.  Experimental Realization of Teleporting an Unknown Pure Quantum State via Dual Classical and Einstein-Podolsky-Rosen Channels , 1997, quant-ph/9710013.

[7]  Dragomir N Neshev,et al.  Spontaneous parametric down-conversion and quantum walks in arrays of quadratic nonlinear waveguides. , 2012, Physical review letters.

[8]  D. Bouwmeester,et al.  The Physics of Quantum Information , 2000 .

[9]  Albert Einstein,et al.  Can Quantum-Mechanical Description of Physical Reality Be Considered Complete? , 1935 .

[10]  K. Itoh,et al.  Ultrafast Processes for Bulk Modification of Transparent Materials , 2006 .

[11]  Bahaa E. A. Saleh,et al.  Entangled-Photon Generation from Parametric Down-Conversion in Media with Inhomogeneous Nonlinearity , 2002 .

[12]  Ekert,et al.  Practical quantum cryptography based on two-photon interferometry. , 1992, Physical review letters.

[13]  Dirk Bouwmeester,et al.  The physics of quantum information: quantum cryptography, quantum teleportation, quantum computation , 2010, Physics and astronomy online library.

[14]  Kimble,et al.  Unconditional quantum teleportation , 1998, Science.

[15]  Andreas Tünnermann,et al.  Control of directional evanescent coupling in fs laser written waveguides. , 2007, Optics express.

[16]  H. Weinfurter,et al.  Experimental Entanglement Swapping: Entangling Photons That Never Interacted , 1998 .

[17]  A. Politi,et al.  Quantum Walks of Correlated Photons , 2010, Science.

[18]  A. Schreiber,et al.  A 2D Quantum Walk Simulation of Two-Particle Dynamics , 2012, Science.

[19]  D. Christodoulides,et al.  Classical analogue of displaced Fock states and quantum correlations in Glauber-Fock photonic lattices. , 2011, Physical review letters.

[20]  Stefan Nolte,et al.  Discrete optics in femtosecond-laser-written photonic structures , 2010 .

[21]  S. Longhi.  Photonic Bloch oscillations of correlated particles. , 2011, Optics letters.

[22]  I. Walmsley,et al.  Spectral information and distinguishability in type-II down-conversion with a broadband pump , 1997 .

[23]  K. Laiho,et al.  Spatial modes in waveguided parametric down-conversion , 2009, 0904.4668.

[24]  S. Nolte,et al.  Hexagonal waveguide arrays written with fs-laser pulses , 2006 .

[25]  H. Weinfurter,et al.  Experimental quantum teleportation , 1997, Nature.

[26]  Yaron Silberberg,et al.  Discrete Solitons in Optics , 2008 .