1. 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

2. UW Physics Single-Photon Source’s Applications ⇝ Quantum Key Distributions ⇝ Photon-Atom Entanglements

3. UW Physics 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.QISET2004.pdf

4. UW Physics 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.

5. UW Physics Ba138’s Energy Level as Single Photon Source ⇝ The 6P 1/2 -6S 1/2 is chosen as cool transition; 650nm red laser keep the ion off 5D 3/2 state. ⇝ Spontaneous decays from both 6P 1/2 and 6P 3/2 can be candidates for single photon source. ⇝ The 6P 3/2 -5D 5/2 transition can only be achieved by LED with a low efficiency

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

7. UW Physics Apparatus ⇝ Homemade Micro-Objective NA=.15~.26 ⇝ Fiber coupled deshelving LED @ 615nm W. Alt Optik 113, No. 3 (2002) 142–144

8. UW Physics Ion-Photon Entanglement ⇝ Pump Ti-Sapphire at higher power to get 493nm pulses; avoid LED’s low pumping efficiency and sideband difficulties. ⇝ When the ion spontaneously decay to 6S 1/2 state, it goes randomly to two qubit states. This entangle the photon’s frequencies with the ion’s final states

9. UW Physics Future Plan ⇝ Fiber coupled single photon source ⇝ Trap improvement to increase collection efficiency ⇝ Remote ion entanglement through photons

10. UW Physics 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