Development of single-photon source based on single trapped barium ions

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Development of single-photon source based on
single trapped barium ions

• Shu, Gang
• Department of Physics
• University of Washington

JTuB6 Quantum Sensing and Imaging II
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Single-Photon Sources Applications

• Quantum Key Distributions
• Photon-Atom Entanglements

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Different Types of Single Photon Sources

• Laser Attenuation
• Single Atoms/Artificial Atoms
• Trapped Ions
• Quantum Dots
• Correlated Photon Sources
• Spontaneous Parametric Down-conversion

SaeWoo Nam, http//qubit.nist.gov/qiset-PDF/Nam.QI
SET2004.pdf
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Ion trap

• Several W of RF is applied to the diagonal rods
  to generate rotating potential well to trap ions
  Caps with DC voltage confine ions axial motions.
• Lasers shine on ions to cool them down.
• Microscope-objective images the ion on to cameras
  or PMTs for detection and monitoring.

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Ba138s Energy Level as Single Photon Source

• The 6P1/2-6S1/2 is chosen as cool transition
  650nm red laser keep the ion off 5D3/2 state.
• Spontaneous decays from both 6P1/2 and 6P3/2 can
  be candidates for single photon source.
• The 6P3/2-5D5/2 transition can only be achieved
  by LED with a low efficiency

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Apparatus
EMCCD camera and correlator measuring HBT
interference
G. Howell FWN6
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Apparatus

• Homemade Micro-Objective
• NA.15.26
• Fiber coupled deshelving LED _at_ 615nm

W. Alt Optik 113, No. 3 (2002) 142144
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Ion-Photon Entanglement

• Pump Ti-Sapphire at higher power to get 493nm
  pulses avoid LEDs low pumping efficiency and
  sideband difficulties.
• When the ion spontaneously decay to 6S1/2 state,
  it goes randomly to two qubit states. This
  entangle the photons frequencies with the ions
  final states

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Future Plan

• Fiber coupled single photon source
• Trap improvement to increase collection
  efficiency
• Remote ion entanglement through photons

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Acknowledgement

• PI Dr. Boris Blinov
• Graduate students
• Nathan Kurz
• Matt Dietrich
• Gary Howell
• Adam Kleczewski
• Undergraduates
• Ryan Bowler
• Viki Mirgon
• Joanna Salacka
• Joseph Pirtle
• Sanghoon Chong

Work funded by University of Washington Royalty
Research Fund Army DURIP