Probing the Rydberg spectrum of strontium – group meeting 22-06-08 Probing the Rydberg spectrum of strontium James Millen
Dec 19, 2015
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
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.
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
Pushing higher
Probing the Rydberg spectrum of strontium – group meeting 22-06-08
5s125s 1S0
5s136s 1S0
5s137s 1S0