Sisyphus Cooling

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Sisyphus Cooling
Sisyphus Cooling
Justin M. Brown
November 8, 2007
Sisyphus Effect
Jean Dalibard and Claude Cohen-Tannoudji (1989)
Model to describe sub-Doppler cooling
Real atoms have more than two levels
Atoms always travel up
a hill to decrease KE
Sub-Doppler Cooling
1
 pump 

Doppler Limit

k BTD  
2
Consider Atomic Zeeman Structure
Approach Recoil Limit
k BTR
 2k 2

2M
Polarization Gradient
Counter-propagating
perpendicular linear polarizations
Polarization Gradient from lightshifts
Lightshifts
Limitations
• Must Doppler cool first!
– Only works over narrow range of velocities
– Traveling over multiple potential hills averages out
• Doesn’t work if KE > Uhill
• Detune laser further and reduce intensity
• Cannot break recoil limit – always emit photon
2
2
 k
k BTR 
2M
Experimental Implementation
87-Rubidium in an optical dipole trap
Circular polarization pumps to end state
Miller, K. W., Durr, S, and Weinman, C. Rf-induced Sisyphus cooling in an optical trap.
Phys. Rev. A, 66(023406), August 2002.
Experimental Implementation
Miller, K. W., Durr, S, and Weinman, C. Rf-induced Sisyphus cooling in an optical trap.
Phys. Rev. A, 66(023406), August 2002.

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