Status of the GEO 600 squeezed-light laser
  In the course of the high-frequency upgrade of GEO 600, its optical configuration was extended by a squeezed-light laser [1]. Recently, a non-classically enhanced measurement sensitivity of GEO 600 was reported [2]. In this paper, a characterization of the squeezed-light laser is presented. Thereupon, the status of the integration into GEO 600 is reviewed, focussing on the sources of optical loss limiting the shot noise reduction by squeezing at the moment. Finally, the possibilities for a future loss reduction are discussed. 
Alexander Khalaidovski, Henning Vahlbruch, Nico Lastzka, Christian   Graef, Harald Lueck, Karsten Danzmann, Hartmut Grote an...
quant-ph physics.optics