GENERATING AND DISTRIBUTING TWO-PHOTON ENTANGLED SPATIAL QUDITS

We report an experiment to generate and propagate two entangled spatial qudits, [Formula: see text]-dimensional quantum systems, using spontaneous parametric down-conversion. The manipulation, via pump beam, of the transverse spatial correlation between the photon pairs is explored. Inserting apertures with [Formula: see text]-slits in the arms of the down-converted photons, we associate the qudit space with the [Formula: see text] possible paths followed by each photon. Experimental results for qudits with [Formula: see text] and 8 are shown. We demonstrate that the generated states cannot be classically correlated. We also show the propagation of entangled states of spatial qudits. Their free-space distribution is performed at the laboratory scale and the propagated states maintain a high fidelity with their original form.

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TWO-PHOTON HIGH-DIMENSIONAL SPATIAL ENTANGLEMENT: THEORY AND EXPERIMENT

Modern Physics Letters B ◽

10.1142/s0217984906009566 ◽

2006 ◽

Vol 20 (01) ◽

pp. 1-23 ◽

Cited By ~ 11

Author(s):

LEONARDO NEVES ◽

G. LIMA ◽

J. G. AGUIRRE GÓMEZ ◽

C. H. MONKEN ◽

C. SAAVEDRA ◽

...

Keyword(s):

Quantum Systems ◽

High Dimensional ◽

Entangled States ◽

Type Ii ◽

Opaque Screen ◽

Two Photon ◽

Parametric Down Conversion ◽

Experimental Works ◽

Maximally Entangled States ◽

Down Conversion

We review recent theoretical and experimental works where are proposed and demonstrated how to use photon pairs created by spontaneous parametric down-conversion to generate entangled states of D-dimensional quantum systems, or qudits. This is the first demonstration of high-dimensional entanglement based on the intrinsic transverse momentum entanglement of the type-II down-converted photons. The qudit space is defined by an aperture made up of an opaque screen with D slits (paths), placed in the arms of the twin photons. By manipulating the pump beam profile we can prepare different entangled states of these possible paths. We focus our attention on an important case for applications in quantum information: the maximally entangled states. Experimental results for qudits with D=4 and D=8 are shown and measuring a two-photon conditional interference, we also demonstrate the nonclassical character of the correlations.

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MULTIMODE HONG–OU–MANDEL INTERFEROMETRY

Modern Physics Letters B ◽

10.1142/s0217984905008050 ◽

2005 ◽

Vol 19 (01n02) ◽

pp. 1-19 ◽

Cited By ~ 4

Author(s):

S. P. WALBORN ◽

W. A. T. NOGUEIRA ◽

A. N. de OLIVEIRA ◽

S. PÁDUA ◽

C. H. MONKEN

Keyword(s):

Quantum Information ◽

Pump Beam ◽

Basic Theory ◽

Experimental Results ◽

Two Photon ◽

Photon Pairs ◽

Transverse Profile ◽

Parametric Down Conversion ◽

Pump Signal ◽

Down Conversion

We review some recent experiments based upon multimode two-photon interference of photon pairs created by spontaneous parametric down-conversion. The new element provided by these experiments is the inclusion of the transverse spatial profiles of the pump, signal and idler fields. We discuss multimode Hong–Ou–Mandel interference, and show that the transverse profile of the pump beam can be manipulated in order to control two-photon interference. We present the basic theory and experimental results as well as several applications to the field of quantum information.

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Generation of Pure State Photon Triplets in the C-Band

Micromachines ◽

10.3390/mi10110775 ◽

2019 ◽

Vol 10 (11) ◽

pp. 775 ◽

Cited By ~ 1

Author(s):

Xi-Rong Su ◽

Yi-Wen Huang ◽

Tong Xiang ◽

Yuan-Hua Li ◽

Xian-Feng Chen

Keyword(s):

Pure State ◽

Schmidt Number ◽

Second Order ◽

Conversion Process ◽

Gaussian Filter ◽

Periodically Poled ◽

Two Photon ◽

Parametric Down Conversion ◽

Photon States ◽

Down Conversion

In this work, the cascaded second-order spontaneous parametric down-conversion (SPDC) is considered to produce pure state photon triplets in periodically poled lithium niobite (PPLN) doped with 5% MgO. A set of parameters are optimized through calculating the Schmidt number of two-photon states generated by each down-conversion process with different pump durations and crystal lengths. We use a Gaussian filter in part and obtain three photons with 100% purity in spectrum. We provide a feasible and unprecedented scheme to manipulate the spectrum purity of photon triplets in the communication band (C-band).

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