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

Probing the Rydberg spectrum

of strontium

James Millen

Level scheme

(5s2) 1S0

461nm

32MHz

(5s5p) 1P1

(5sns) 1S0 (5snd) 1D2

Continuum ~413nm

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

Experimental set up

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

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

Detection

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

• We use our field plates to accelerate and guide chargetowards the MCP

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.

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.

Results

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

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* = √(Rsr/Tn)Tn = Eion - E

1S0

δ=3.27

1D2

δ=2.38

Analysis

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

5s70s 1S0

5s71s 1S0

5s72s 1S0

5s73s 1S0

5s74s 1S0

5s71d 1D25s72d 1D2

5s73d 1D2

5s74d 1D2 5s75d 1D2

Analysis

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

Pushing higher

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

5s125s 1S0

5s136s 1S0

5s137s 1S0

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.