1. Excited state spatial distributions Graham Lochead 20/06/11

2. Outline Rydberg spatial distribution Locked coupling laser spectra Preliminary spatial distributions Graham Lochead 20/06/11

3. Motivation Column density (arb. units) Distance (microns) Ground state Excited state Separation Interaction energy Graham Lochead 20/06/11

4. Experimental procedure Automatic translation stage Lens setup Graham Lochead 20/06/11

5. Autoionization Allows independent Rydberg excitation and investigation Ion detection is very sensitive 5s 2 5s5p5sns(d)5pns(d)5s 1/2 + Graham Lochead 20/06/11

6. Ion spectrum experimental setup Time Probe + Coupling (1 μs) MOT + Zeeman Electric field pulse (5 μs) MOT + Zeeman Repeat 408 pulse (1 μs) Probe frequency stepped Camera image taken for atom number 100 ns between excitation pulses 408 not at focus Graham Lochead 20/06/11

7. 56D spectrum Example ion signal Integrate to get each point Example Rydberg spectrum Graham Lochead 20/06/11

8. MOT coil turn off Varying time between MOT coil switch off and excitation beams Zeeman effect Previously did not have the resolution to see this splitting Set Δt to be 400 μs to avoid this Graham Lochead 20/06/11

9. Ion spectrum characterisation Graham Lochead

10. Translation experiment setup Time Probe + Coupling (1 μs) MOT + Zeeman Electric field pulse (5 μs) MOT + Zeeman Repeat 408 pulse (1 μs) Probe frequency set to max ion signal 408 is at focus Translation stage stepped Graham Lochead 20/06/11

11. Translation signal-to-noise Focused 408 addresses few atoms Autoionising signal may be small Spontaneous ionization is a problem D states are repulsive Graham Lochead 20/06/11

12. Chi-squared fit Gaussian fit to all data Graham Lochead 20/06/11 Do not expect Rydberg Blockade at this n or density Average of three translation runs with standard error

13. Reaching Rydberg Blockade Graham Lochead Two ways to reach blockade: Increase n Increase density

14. Higher n error signals Graham Lochead 20/06/11 Main constraint for higher n is laser locking signal n -3

15. Repump lasers 5s 2 1 S 0 5s5p 1 P 1 5s4d 1 D 2 5s6s 3 S 1 5s5p 3P23P2 3P13P1 3P03P0 461 nm 679 nm707 nm Current cooling scheme has leak Repumping increases density by approximately order of magnitude Graham Lochead 20/06/11

16. Summary / Outlook Repeatable ion spectra Preliminary spatial distributions Need to increase density Graham Lochead 20/06/11