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Characterizing Photonic Spatial States

Sebastião Pádua

Physics Department - Federal University of Minas Gerais – Belo Horizonte - Brazil

Paraty 2009, September 08 2009

Informação Quântica

Enlight and Quantum Optics Laboratory

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Outline

• Transfer of information from the pump beam• Generation and propagation of qudits• Quantum Tomography of qubits with SLM• Progress in four photons production

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Two photon state

Angular Spectrum Transference

ks = ki = kp/2

ms = mi = 1/2

R = (rs+ri)/2

NaNa 2

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D. Prichard, et. al, Phys. Rev. Lett. (1995)

Lithography

Double-slit – proof of principleM. D’Angelo, M. V. Chekhovaand Y. Shih, Phy. Rev. Lett. 87 013692 (2001).

OBJECT: DOUBLE SLIT

Laser, = 826 nm

Laser, = 413 nm

Twin Photons = 826 nm

Optics Communications

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Quantum Tomography with a Spatial Light Modulator

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-1500 -1000 -500 0 500 1000 15000

2000

4000

6000

8000

10000

12000

14000

sfundo25 sfundo130 sf25x130 sf130x25

Co

un

ts in

5s

Position (m)

Phases: 0, 0 , -60.7 , 80,6

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=

The values of pi are obtained from measurements.

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22

=

Slits are partially blocked and phases are changed by the SLM

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LiIO3

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Laser He-Cd

LiIO3

M1

M2

CSLM

L1

L2

DoubleSlit

f

f

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Goal: 2 qubits and 2 qutrits.

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• Students: Juliana Gontijo, Wanderson Pimenta, Mariana Barros, Marco Aurélio Carvalho, Breno Teixeira – Physics Department - UFMG

• Pos-doc : Dr. José Ferraz• Prof. Marcelo Terra Cunha – Mathematics Department – UFMG

• Univ. De Concepción - Chile: Profs. Leonardo Neves, G. Lima, A. Delgado, and Carlos Saavedra

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PPKTP – SPDC – Type II

Angular Spectrum Transference

Controlling the transverse correlation in QPM parametric down-conversion, O. Cosme, A. Delgado, G. Lima, C. H. Monken and S. Pádua – arXiv: 0906.473v1(2009)[quant-ph].

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PPKTP

Quantum image formation

Image of a double-slit placed in the pump beam path and detected at the image plane by coincidence

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Profile of the laser beam and 4-photon coincidence count in the horizontal direction

SPDC state with four photons- PPKTP

Transfer of the pump angular spectrum to the four photon SPDC quantum state

Profile of the laser beam and 4-photon coincidence count in the vertical direction

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Image of a displaced wire in the pump beam path and 4-photon counts

SPDC state with four photons- PPKTP

Transfer of the pump angular spectrum to the four photon SPDC quantum state