1. Probing the Rydberg spectrum of strontium – group meeting 22-06-08 Probing the Rydberg spectrum of strontium James Millen

2. Level scheme (5s 2 ) 1 S 0 461nm 32MHz (5s5p) 1 P 1 (5sns) 1 S 0 (5snd) 1 D 2 Continuum ~413nm Probing the Rydberg spectrum of strontium – group meeting 22-06-08

3. Experimental set up Probing the Rydberg spectrum of strontium – group meeting 22-06-08

4. Detection Probing the Rydberg spectrum of strontium – group meeting 22-06-08 Primary source of detection is a micro-channel plate (MCP), set up to detect ions. Can charge the grid to help guide charges to the MCP

5. Detection Probing the Rydberg spectrum of strontium – group meeting 22-06-08 We use our field plates to accelerate and guide charge towards the MCP

6. Signal analysis Probing the Rydberg spectrum of strontium – group meeting 22-06-08 Can directly count using our FPGA card (theoretical 25ns resolution, we used 1μs resolution max) Though nice to actually count ions, discriminator can become saturated Otherwise, use the signal direct from MCP amplifier, and average on the scope.

7. Rydberg spectrum acquisition Probing the Rydberg spectrum of strontium – group meeting 22-06-08 The MOT is continually on and being filled, as is the 413nm laser. There is a 30μs field pulse every 500μs. There is a slow (1s) laser scan, 256 averages are taken, and the data is binned.

8. Results Probing the Rydberg spectrum of strontium – group meeting 22-06-08

9. Analysis Probing the Rydberg spectrum of strontium – group meeting 22-06-08 Can use quantum defect analysis to try and identify series δ = n – n*n* = √(R sr /T n ) T n = E ion - E 1 S 0 δ=3.27 1 D 2 δ=2.38

10. Analysis Probing the Rydberg spectrum of strontium – group meeting 22-06-08 5s70s 1 S 0 5s71s 1 S 0 5s72s 1 S 0 5s73s 1 S 0 5s74s 1 S 0 5s71d 1 D 2 5s72d 1 D 2 5s73d 1 D 2 5s74d 1 D 2 5s75d 1 D 2

11. Analysis Probing the Rydberg spectrum of strontium – group meeting 22-06-08

12. Pushing higher Probing the Rydberg spectrum of strontium – group meeting 22-06-08 5s125s 1 S 0 5s136s 1 S 0 5s137s 1 S 0

13. Outlook Probing the Rydberg spectrum of strontium – group meeting 22-06-08 Move to a cleaner experiment. Identify lines (do some theory). Also, why do we see ions at all at lower n? Make some Stark maps.