Photon echo in the super-radiant light scattering from a Bose-Einstein condensate

Abstract

Super-radiant Rayleigh scattering from a Bose-Einstein condensate, driven by a single far-detuned laser beam, is strongly limited by dephasing due to inhomogeneous broadening. We demonstrate that the dephasing can be reversed applying a Bragg pulse of area pi after the first superradiant scattering, stimulating a superradiant echo and inducing a further transfer of atoms from the initial condensate to a condensate with relative momentum 2hk in the direction of the laser

Multiple photon-echo rephasing of coherent matter waves

“…Some transverse effects are also negligible, which will be discussed in Section 4. In the following, we neglect the atomic collision term, because μ hωr is satisfied [22] and a s is much less than the transverse radius [26]. So the collision term won't significantly influence the results until it leads to the phase relaxation of the BEC system in a long time scale [13,32].…”

“…The theoretical model of the BEC's interaction with light field in one-dimension geometry is the Maxwell-Gross-Pitaevskii (MGP) equations [22] which apply to high momentum case once the Bragg resonance condition is satisfied:…”

“…The one-order photon echo technique in the BEC makes use of the optically induced Bragg diffraction with weak pump beam [22][23][24][25]. A cigar-shaped one-dimensional BEC is prepared in a magnetic or magneto-optical trap with comparatively weak confinement in the longitudinal direction [24,26] or by releasing a three-dimensional BEC into a waveguide [27].…”

“…This paper is organized as follows. In Section 2, we put forward a multipulse protocol to induce multiple photon echo processes in a BEC, based on the one-order echo principle [22]. The evolution of the BEC's mode population is given, demonstrating the high efficiency of momentum transfer.…”

High Order Momentum States by Light Wave Scattering

“…Because the above traditional superradiant-scattering configuration involves many atomic side modes coupled together, to simplify it, we chose another configuration where a pump beam travels along the long axis of the BEC. This scheme is widely studied in photon echo (Piovella et al, 2003), decoherence (Fallani et al, 2005), spatial distribution effects and self-organized formation of dynamic gratings (Hilliard et al, 2008). Since the pulse length is far longer than the initial spontaneous process (Zobay & Nikolopoulos, 2006), we choose the semi-classical theory which can well describe the experimental results (Bar-Gill et al, 2007;Yang et al, 2008;Zobay & Nikolopoulos, 2006).…”