Delaubert, VincentTreps, NicolasHarb, Charles C.Lam, Ping KoyBachor, Hans2016-06-082016-06-080146-9592http://hdl.handle.net/1885/102337We consider the problem of measurement of optical transverse profile parameters and their conjugate variable. Using multi-mode 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 their optimal encoding and detection 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.© 2006 Optical Society of America2005-12-1910.1364/OL.31.001537