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SUMMARY:Just a few atoms: Imaging for matter-waves optics - Wolf von Klitz
 ing (FORTH\, Crete)
DTSTART:20111116T110000Z
DTEND:20111116T120000Z
UID:TALK33977@talks.cam.ac.uk
CONTACT:6270
DESCRIPTION:Just a few atoms:\nImaging for Matter-Waves Optics\nM. Pappa\,
 1 P.C. Condylis\,1 M. Baker\,1 D. Sahagun Sanchez\,1\nA. Lazoudis\,1 G. 
 Konstantinidis\,1 O. Morizot\,1 and W. von Klitzing1\, \n1IESL{FORTH\nIns
 titute of Electronic Structure and Lasers\,\nFoundation of Research and Te
 chnology - Hellas\,\nGR711 10\, Heraklion Crete\, Greece\nTel +30-2810-39-
 1546\nInterferometry with massive particles oers an enormous increase in 
 sensitivity and accuracy both for fundamental\nand applied physics. One of
  the key aspects is the fact that the number of massive particles are pres
 erved throughout\nthe experiment. This can be exploited\, for example\, in
  Heisenberg limited detection\, where the sensitivity scales with\nthe num
 ber of particle as opposed to its square root. It would therefore be of gr
 eat interest to be able to image low\natom numbers at the atom shot-noise 
 limit with good spatial resolution. Fluorescence imaging oers single part
 icle\nsensitivity[1] but usually requires the atom to be conned in a trap
 ping potential. Recently\, this technique has\nbeen extended to images of 
 atoms falling through a sheet of light.[2] Multichannel plates can be empl
 oyed to detect\nsingle metastable atoms falling upon it.[3] However\, a im
 aging technique which works in free-space has single-particle\nsensitivity
  is yet to be demonstrated.\nTraditional absorption imaging oers very goo
 d resolution and easy of use. Unfortunately\, due to technical noise it\nr
 arely reaches shot-noise limited performance. In this talk I will review t
 he limits of traditional absorption imaging\nand then demonstrate diracti
 ve dark ground imaging as an ultra-sensitive imaging technique capable ima
 ging\natomic ensembles of tens of atoms with Fourier-limited spatial resol
 ution. We demonstrate an improvement by an\norder of magnitude in sensitiv
 ity\, when compared to absorption imaging\, or time-resolution when compar
 ed to \nu-\norescence imaging. Finally\, we will address the limits of coh
 erent imaging\, where the atom shot-noise approaches unity.\nFIG. 1: Dark-
 ground image of a two component spinor BEC of 28 atoms after Stern-Gerlach
  separation into its dierent magnetic\nhyperne states. From left to righ
 t: about 7 atoms in the the hf = 2\;mf = 􀀀2i state\, 23 atoms in the hf
  = 2\;mf = 􀀀1i state\,\nand 34 atoms in the hf = 2\;mf = 0i state. The 
 other states are not populated. The clouds have a 1=e2 radius of 5:7  4:2
 m.\nThe exposure time was 200 s:\n[1] Localized visible Ba+ mono-ion osc
 illator\,W. Neuhauser\, M. Hohenstatt\, P. E. Toschek\, and H. Dehmelt \, 
 Physical Review\nA (1980).\n[2] Single-particle-sensitive imaging of freel
 y propagating ultracold atoms\, R. Bucker\, A. Perrin\, S. Manz\, T. Betz
 \, C. Koller\, T.\nPlisson\, J. Rottmann\, T. Schumm\, and J. Schmiedmayer
  \, New Journal of Physics (2011).\n[3] Hanbury Brown Twiss eect for ultr
 acold quantum gases\, M. Schellekens\, R. Hoppeler\, A. Perrin\, J. V. Gom
 es\, D. Boiron\,\nA. Aspect\, and C. I. Westbrook\, Science (2005).\nElec
 tronic address: wvk@bec.gr\; URL: http://www.bec.gr
LOCATION:Rutherford building\, Seminar Room B
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