Transcript Single Site Addressability in a CO2 Lattice

Pulsed laser spectroscopy
in strontium
Graham Lochead
07/09/09
Outline
• Strontium project update
• Ladder EIT
• Electron shelving spectroscopy
Graham Lochead
07/09/09
Project update
• Pyramid MOT
• Cavity
• 412 nm laser
• 420 nm laser
Graham Lochead
07/09/09
Optical setup
Dispenser
Baffle
Dye
laser
Pump
laser
Aperture
461 nm light
from fibre
Lens FPD
Cell
Dye laser parameters
• ~5 mm beam diameter
• 10 Hz repetition
• 10 ns pulse duration
Graham Lochead
07/09/09
• ~20 mJ per pulse
• ~5 nm tuning range
• ~2 GHz linewidth
Ladder EIT (I)
5snd 1D2
413 nm ωr
5s5p 1P1
ωe
461 nm
5s2 1S0
Δc
ωc
le>
lr>
Probe: 5s2 1S0 → 5s5p 1P1
Couple: 5s5p1P1 → 5snd1D2
Δp
ωp 1P lifetime ~ 5 ns, Rydberg lifetime ~ 10 μs
1
lg>
a  e e e  r r r



 i t
 i   p e p e g   c e ict r e  h.c.
2
 0

p / 2
0


    p / 2   p
c / 2 
 0


/
2

(



)
c
p
c 

 p   p  e
c  c  r
J.P. Marangos, J. Mod. Opt 45, p. 471-503 (1998)
Graham Lochead
07/09/09
Ladder EIT (II)
Diagonalization of the Hamiltonian leads to new eigenstates:
  sin  sin  g  cos e  cos sin  r
0  cos g  sin  r
  sin  cos g  sin  e  cos cos r
p
  arctan
c
 2p  c2
1
  arctan
2
p
For Ωc >> Ωp and Δp = 0
  r e
2 Probe couples to excited state of
both |+> and |-> which have
equal but opposite transition
0  g
probabilities, thus on-resonance
probe not absorbed
  r e
2
Coherent process – decoherence
effects increase absorption




Graham Lochead
07/09/09
Simulations
• Solve three level optical Bloch equations
• Rydberg transition Rabi frequency from
oscillator strength S.-U. Haq et al., EPJD 44, p. 439 (2007)
Absorption
1
2 / 4
 21  i p 
 31  i( p   c )
Graham Lochead
07/09/09
Catastrophe!
Hole
• Cell cleaned out
• Reassembled and reevacuated
• Absorption seen again
• Hole drilled in viewport
• Vacuum lost
Graham Lochead
07/09/09
Electron shelving
5snd 1D2
5s5p 1P1
461 nm
Ωp
5s2 1S0
Probe: 5s2 1S0 → 5s5p 1P1
435 nm
Couple: 5s2 1S0 → 5snd
1D
435 nm
2
Off-resonant
two photon
Ωc
excitation to Rydberg state
Unlikely to see EIT due to large decoherence
Rydberg state has a long lifetime relative to 1P1
P. Thoumany et al., Optics Letters 34, p. 1621-1623 (2009)
Graham Lochead
07/09/09
Outlook
• Change dye to attempt electron shelving
• Finish building pyramid MOT
Graham Lochead
07/09/09