Transcript Single Site Addressability in a CO2 Lattice

Dipole-dipole interactions in
Rydberg states
Outline
• Strontium experiment overview
• Routes to blockade
• Dipole-dipole effects
Team strontium
Matt Jones
Me
Charles Adams
Danielle
Boddy
Dan
Sadler
Christophe
Vaillant
Rydberg physics
Rydberg atoms:
• States of high principal n
• Strong, tunable interactions
Ground state
Column
density
Excited state
Position
Spatial measurements
Automatic
translation state
Lens setup
Autoionization
5pns(d)
λ3 = 408 nm
5s Sr+
5sns(d)
λ2 = 413 nm
5s5p
λ1 = 461 nm
5s2
• Resonant ionization process
• Increases signal over spontaneous ionization
• Independent excitation and detection
• Can give spectral and temporal information
Preliminary results
•
•
•
•
•
Probe +
408
Electric
Coupling
pulse
field pulse
(1 μs)
(1 μs)
(5 μs)
MOT +
Zeeman
MOT +
Zeeman
Time
Repeat
~106 atoms at 5 mK
Camera image for atom number
408 is focused to 10 μm
Translation stage stepped
Ions detected on an MCP
Increasing density
5s6s 3S1
Current cooling scheme has leak
679 nm
5s5p 1P1
707 nm
5s4d 1D2
3P
2
3P
1
461 nm
5s5p
5s2 1S0
3P
0
Repumping increases density by
approximately an order of magnitude
Förster zeros
Long range van der Waals interaction couples pairs of states
: radial part of the interaction
: angular part of the interaction
Förster zero is where
is zero
Sum over all final states to get
total interaction
T.G. Walker and M. Saffman, PRA 77, 032723 (2008)
Quantization coils I
Apply magnetic field to define quantization axis
 Polarization well defined, can excite specific mJ
Need to switch fast
 Avoid losing density
External coils too slow
 Eddy currents in chamber
Quantization coils II
Solution: Use internal coils
Vertical excitation beams are orthogonal to autoionizing beam
Internuclear axis
Internuclear axis aligned
with quantization axis
 mJ projection good
Internuclear axis not aligned
with quantization axis
 mJ projection varies
Solution: Use S states or make geometry 1D
Summary
• Signal to noise of spatial measurements is good
• Close to blockade densities
• Need to control polarization to avoid Förster zeros