Optical pattern formation with a two-level nonlinearity

Abstract

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Thick-medium model of transverse pattern formation in optically excited cold two-level atoms with a feedback mirror

“…For long pulses (greater than 10 μs), with blue detuning, optomechanical [15,16] density modulations were shown to be dominant in optimum conditions [8], whereas for shorter pulses (less than 2 μs), pattern formation was found to be consistent with the standard two-level electronic nonlinearity [9]. The results of Ref.…”

“…The results of Ref. [9] constitute the observation of pattern formation in a system with a saturable electronic two-level nonlinearity.…”

“…Spatial coupling of transversely separate regions inside the medium is provided by diffraction [6,7]. Recently, we used this setup to observe long-range hexagonal ordering in a thermal cold-atom gas, breaking the continuous spatial symmetries of the initial system [8,9]. This matches interest in a related scheme for patterns in cold-atom systems interacting with two independent counterpropagating input fields [10][11][12][13][14].…”

“…The forward (F ) and backward (B) propagating beams interfere inside the cloud. The experimental parameters are a cloud of 87 Rb atoms with T = 200 μKd r i v e na t a detuning of δ>0 from the F = 2 → F ′ = 3 transition of the D 2 line, an optical density (base e) in line center equal to 210, and an effective sample size (FWHM of cloud) L = 8.5mm [9]. one or more envelope curves.…”

Observation of Optomechanical Strain in a Cold Atomic Cloud

“…Interactions are also tuned by optical Feshbach resonance [17], optical cavities [18], or radio frequency Feshbach resonance [19]. Interactions can be induced by shining a laser beam on the atoms and creating a feedback mechanism to their response by an externally pumped cavity or a half cavity [20][21][22][23][24][25]. The electrostriction force reported here is a new kind of induced force between atoms, and may be useful in cold atoms and quantum degenerate atom experiments.…”