A detector for continuous measurement of ultra-cold atoms in real time
  We present the first detector capable of recording high-bandwidth real time atom number density measurements of a Bose Einstein condensate. Based on a two-color Mach-Zehnder interferometer, our detector has a response time that is six orders of magnitude faster than current detectors based on CCD cameras while still operating at the shot-noise limit. With this minimally destructive system it may be possible to implement feedback to stabilize a Bose-Einstein condensate or an atom laser. 
C. Figl, L. Longchambon, M. Jeppesen, M. Kruger, H. A. Bachor, N. P.   Robins and J. D. Close