Transcript Single Site Addressability in a CO2 Lattice

Excitation control of a cold
strontium Rydberg gas
Graham Lochead, 12/12/11
Team strontium
Matt Jones
Me
Charles Adams
Danielle
Boddy
Dan
Sadler
Graham Lochead, 12/12/11
Christophe
Vaillant
Rydberg physics
Rydberg atoms:
• States of high principal n
• Strong, tunable interactions
Ground state
Column
density
Excited state
Position
Graham Lochead, 12/12/11
Spatial autoionization
5pns(d)
λ3 = 408 nm
5s Sr+
5sns(d)
λ2 = 413 nm
5s5p
λ1 = 461 nm
5s2
Graham Lochead, 12/12/11
Outline
• Quantization axis
• Focused coupling beam
• Rydberg transition saturation
Graham Lochead, 12/12/11
Experimental procedure
• ~106 atoms at 5 mK
• Camera image for atom number
• 408 is focused to 10 μm
• Translation stage / probe
…frequency stepped
• Ions detected on an MCP
Probe +
408
Electric
Coupling
pulse
field pulse
(1 μs)
(1 μs)
(5 μs)
MOT +
Zeeman
MOT +
Zeeman
Time
Repeat
Graham Lochead, 12/12/11
Quantization axis
mJ = -2
-1
0
+1
+2
J=2
J=1
J=0
• States degenerate – can’t select
• Stray field broadens spectrum
Graham Lochead, 12/12/11
Quantization field
• Magnetic field splits degeneracy
• Stretched states strongest coupled
Can select mJ state
Förster zeros avoided
Graham Lochead, 12/12/11
Field switch on
• Need to switch field on
• Swtich as fast as possible
• Eddy currents a problem
Graham Lochead, 12/12/11
Focusing coupling laser
Why?
Unaddressed Rydberg atoms
1D geometry
Better internuclear projection
Graham Lochead, 12/12/11
Focused coupling laser
Similar lens setup to autoionizing laser
Translate 408 to find focus
Graham Lochead, 12/12/11
“Saturation” effect
Large increase in Rabi frequency
“Saturation” seen in amplitude
Not Coulomb blockade as no shift
3-level OBE theory incorrect
Graham Lochead, 12/12/11
Summary
• Can excite specific mJ states
• Focused coupling laser
• Saturation effect to investigate
Graham Lochead, 12/12/11