Coherence-Enhanced Imaging of a Degenerate Bose-Einstein Gas

Abstract

We present coherence-enhanced imaging, an in situ technique that uses Raman superradiance to probe the spatial coherence of an ultracold gas. Applying this technique, we identify the coherent portion of an inhomogeneous degenerate (87)Rb gas and obtain a spatially resolved measurement of the first-order spatial correlation function. We find that the decay of spin gratings is enhanced in high density regions of a Bose-Einstein condensate, and ascribe the enhancement to collective atom-atom scattering. Further, we directly observe spatial inhomogeneities that arise generally in the course of extended-sample superradiance.

High Order Momentum States by Light Wave Scattering

“…A series of experiments (Bar-Gill et al, 2007;Kozuma, Suzuki et al, 1999;Sadler et al, 2007;Schneble et al, 2003;Slama et al, 2007) have sparked related interests in phase-coherent amplification of matter waves (Kozuma, Suzuki et al, 1999;Schneble et al, 2003), quantum information (Bar-Gill et al, 2007), collective scattering instability (Slama et al, 2007), and coherent imaging (Sadler et al, 2007).…”

“…In the superradiant Rayleigh scattering (Bar-Gill et al, 2007;Guo et al, 2008;Inouye et al, 1999;Kozuma, Suzuki et al, 1999;Moore & Meystre, 1999;Pu et al, 2003;Sadler et al, 2007;Schneble et al, 2003;Slama et al, 2007;Zobay & Nikolopoulos, 2006), the spatial and time evolutions of superradiant scattering are studied for a weak pump beam with different frequency components traveling along the long axis of an elongated Bose-Einstein condensate. Through the analysis of the mode competition between the different resonant channels and the local depletion of the spatial distribution, we can get a large number of high-order forward modes by resonant frequency components of the pump beam ).…”

Anisotropy ins-wave Bose-Einstein condensate collisions and its relationship to superradiance

“…Anisotropies are less surprising in a wave context. The process of optically pumped superradiance [27][28][29][30][31][32][33][34][35], which occurs when an elongated atomic cloud is illuminated with light, exhibits strong anisotropies which can be explained in terms of an anisotropic gain medium.…”

Mode competition in superradiant scattering of matter waves

“…No precise analysis of competition between different superradiant scattering modes has been carried out yet. Such analysis would be useful for calibrating precisely superradiance gains and initial Rayleigh scattering rates if one wants to use quantitatively superradiance for the analysis of coherence in Bose gases [5,6]. Analyzing superradiance with non common configurations is also important as combining early stage superradiance described with quantum theory and long timescale superradiance which is well captured within a semi-classical theory taking into account propagation effects is currently a topic of high interest [7,8] We present in this article an experimental analysis of mode competition in superradiance scattering.…”