REALIZATION OF A MAGNETICALLY GUIDED BEAMIN THE COLLISIONAL REGIME
T. Lahaye, Z. Wang, J. Dalibard and D. Guéry-OdelinLaboratoire Kastler Brossel, Ecole Normale Supérieure, 24 rue Lhomond, 75005 Paris (France)
MOTIVATIONAtom lasers from BEC
Injector MOT Magnetic guideand evaporation
OUR PROJECT
PULSED INJECTION
REFERENCES
Radiofrequency outcoupler
[1] E. Mandonnet A. Minguzzi, R. Dum, I. Carusotto, Y. Castin and J. Dalibard, Eur. Phys. J. D 10, 9 (2000).[2] P. Cren, C. F. Roos, A. Aclan, J. Dalibard and D. Guéry-Odelin, Eur. Phys. J. D 20, 107 (2002).[3] C. F. Roos, P. Cren, J. Dalibard and D. Guéry-Odelin, Physica Scripta T105, 19 (2003) and cond-mat/0212060.[4] C. F. Roos, P. Cren, T. Lahaye, J. Dalibard and D. Guéry-Odelin, Laser Physics 13, 605 (2003) and cond-mat/0212147.[5] T. Lahaye, P. Cren, C.F. Roos and D. Guéry-Odelin, Comm. Nonlin. Sci. Num. Sim., 8, 315 (2003) and cond-mat/0211661.[6] C. F. Roos,P. Cren, D. Guéry-Odelin and J. Dalibard, EuroPhys. Lett., 61, 187 (2003).[7] J. M. Vogels, T. Lahaye, C. F. Roos, J. Dalibard and D. Guéry-Odelin, cond-mat/0404560.[8] T. Lahaye, J. M. Vogels, K. Günter, Z. Wang, J. Dalibard and D. Guéry-Odelin, to appear in Physical Review Letters, cond-mat/0405013.
Transpose to an atomic beam the techniques used on atom clouds.Goal: achievement of a continuous and intense cold atomic beam, magnetically guided,
with a low mean velocity.Apply transverse evaporative cooling [1]. If the initial collision rate is highenough, quantum degeneracy can be reached after a few meters.
Low flux < 104 atoms/s1 monolayer on 1 m2 in 3 years
Oven T= 140-170 °C
Oven flux = 1.5 1012 atoms/s
Flux of slow atoms:
2. 1011 atoms/s
at a mean velocity of the order
of 15 m/s.
Anisotropic 3D magnetic gradient
Six beams MOT
Capture rate > 2. 1010 atoms/s
Adjustable launching velocityfrom 0.3 m/s to 3 m/s
Pulsed injection in the guide, overlap after 70 cm propagation:
3 to 4 packets per second: Flux of the order of 7.109 atoms/s
probe
TEMPERATURE MEASUREMENT WITH ONE RF ANTENNA
“Red” trajectory is not evaporated“Blue” trajectory is evaporated
T=380 µK
1.0
0.5
0.00 10 20 30
N’/N
d1, ? ? A2, ? ?dA1 A2
EXPERIMENT WITH TWO ANTENNAS
WITH COLLISIONS d=3 mWITHOUT COLLISIONS
ν1= 8 MHz
Radio frequency (MHz)
N’’/N’
D. Guéry-Odelin, J. M. Vogels, K. Günter, A. Senger, T. Lahaye, J. Dalibard, Z. Wang
Previous members: J. M. Vogels, K. Günter, C. F. Roos, A. Aclan, P. Cren
Rubidium Oven
Zeeman SlowerZeeman Slowerbeam, 780 nm
Rb
MOT beam, ν-MOT beam, ν-
MOT beam, ν+ MOT beam, ν+
x
yz
Probingzone
Magnetic guide
MOTchamber
15 mm400 A
Magnetic gradient300 G/cm
14 mmAtoms
ENTRANCE OF THE MAGNETIC GUIDE
OVEN AND ZEEMAN SLOWERMAGNETO-OPTICAL TRAP
Antenna 1
Antenna 2
TAPERED SECTIONOF THE MAGNETIC
GUIDE
d
Time (s)
24
42
1
1.5
1.0
0.5
0.0
0 3 6
Area
(a.u
.)
00
8
5 10 15 20 25Number of launches
Abso
rptio
n (a
.u.) a) b)
REALIZATION OF A CONTINUOUS BEAM
OUTLOOKSlope to slow down the beam
Start forced evaporative coolingwith many antennas
Dark line MOT.
4.5
met
er
300 G/cmfor I=400 A.
1000 G/cmfor I=400 A.
0.4 meter
EXPERIMENTAL SETUP
1.0
0.5
0.00 10 20
1.0
0.5
0.00 10 20 300 10 20 30
T=380 µK T=280 µK
Heating Cooling
0.5
1.0
1.5
0 1 2 3 4 5
T 2 / T1
η1
THE TEAM
1.0
0.6
0.20 10 20 30 40 50 60
µ
νRF
νRF
νRF
