title: Quantum measurements of spatial conjugate variables: displacement and tilt of a Gaussian beam.
abstract: We consider the problem of measurement of optical transverse profile parameters and their conjugate variable. Using multimode analysis, we introduce the concept of detection noise modes. For Gaussian beams, displacement and tilt are a pair of transverse-profile conjugate variables. We experimentally demonstrate the optimal encoding and detection of these variables with a spatial homodyning scheme. Using higher-order spatial mode squeezing, we show the sub-shot-noise measurements for the displacement and tilt of a Gaussian beam.
authors.affiliation: Australian Research Council Centre of Excellence for Quantum-Atom Optics, The Australian National University, Canberra, Australia. vincent.delaubert@anu.edu.au
authors.forename: Vincent
authors.initials: V
authors.lastname: Delaubert
authors.forename: Nicolas
authors.initials: N
authors.lastname: Treps
authors.forename: Charles C
authors.initials: CC
authors.lastname: Harb
authors.forename: Ping Koy
authors.initials: PK
authors.lastname: Lam
authors.forename: Hans-A
authors.initials: HA
authors.lastname: Bachor