Imaging With Entangled Photons

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Imaging With Entangled Photons

• Timothy Shokair
• Physics 138
• May 10, 2005

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What is Entanglement?

• Term Coined by Schrödinger in response to famous
  1935 EPR Paradox paper.
• EPR claimed Quantum mechanics was incomplete,
  Schrödinger responded with a statement based on
  the Copenhagen Interpretation of QM.
• Paradox was left alone for 30 years until Bell
  came up with his theory on hidden variables.
• Experiment was done by Freedman and Clauser in
  1972 that showed strong evidence against local
  hidden variable theories.
• Further proof by Kwait, Eberhard, Steinberg and
  Chiao that was unambiguous.

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How do we get entangled photons?

• Spontaneous Parametric Down Conversion (SPDC).
• Three Photon process One UV photon into a
  crystal where it is absorbed and two lower energy
  photons emitted.
• The two photons emerge in an entangled state.
• See Keller and Rubin Phys. Rev. A v.52 pg. 1534
  for full theory.

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An Illustration
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The Crystal

• Beta Barium Borate (BBO) highly nonlinear.
• Two types of cuts Type-I, producing photons
  polarized parallel to each other and Type-II
  where they are orthogonal.
• The photons are termed Signal and Idler.

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An Experiment

• Pittman, Shih, Strekalov, and Sergienko performed
  and experiment where they exploited entangled
  photons to create an image.
• University of Maryland Baltimore County December
  1994
• Mathematical Details of the Geometry described in
  a later paper by the same group.

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Schematic of the Experiment
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Results
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Holography Experiment

• Proposed by Abouraddy, Saleh, Sergienko and Teich
  at Boston University in 2001.
• Using similar methods to the UMBC group the
  propose to use entangled photons for 3D
  holography.
• Signal Photon scatters on remote object while the
  Idler is locally manipulated using conventional
  optics.

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The Setup
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Conclusion

• Entangled Photons have been used to create images
  and give the possibility of high resolution.
• Holography could be used in a completely
  non-classical way by imaging a remote object in
  an isolated chamber where light can enter but not
  escape.