9 research outputs found
Hyperfine transition induced by atomic motion above a paraffin-coated magnetic film
We measured transitions between the hyperfine levels of the electronic ground
state of potassium-39 atoms (transition frequency: 460 MHz) as the atoms moved
through a periodic magneto-static field produced above the magnetic-stripe
domains of a magnetic film. The period length of the magnetic field was 3.8 um.
The atoms were incident to the field as an impinging beam with the most
probable velocity of 550 m/s and experienced a peak oscillating field of 20 mT.
Unwanted spin relaxation caused by the collisions of the atoms with the film
surface was suppressed by the paraffin coating on the film. We observed
increasing hyperfine transition probabilities as the frequency of the field
oscillations experienced by the atoms increased from 0 to 140 MHz for the
atomic velocity of 550 m/s, by changing the incident angle of the atomic beam
with respect to the stripe domains. Numerical calculation of the time evolution
of the hyperfine states revealed that the oscillating magnetic field
experienced by the atoms induced the hyperfine transitions, and the main
process was not a single-quantum transition but rather multi-quanta
transitions.Comment: 12 pages, 6 figure
Multi-state interferometric measurement of nonlinear AC Stark shift
We demonstrate measurement of quadratic AC Stark shifts between Zeeman
sublevels in an Rb Bose--Einstein condensate using a multi-state atomic
interferometer. The interferometer can detect a quadratic shift without being
affected by relatively large state-independent shifts, thereby improving the
measurement precision. We measure quadratic shifts in the total spin
state due to the light being near-resonant to the D line. The agreement
between the measured and theoretical detuning dependences of the quadratic
shifts confirms the validity of the measurement. We also present results on the
suppression of nonlinear spin evolution using near-resonant dual-color light
pulses with opposite quadratic shifts.Comment: 7 pages, 6 figure