TEM10 homodyne detection as an optimal small displacement and tilt   measurements scheme
  We report an experimental demonstration of optimal measurements of small displacement and tilt of a Gaussian beam - two conjugate variables - involving a homodyne detection with a TEM10 local oscillator. We verify that the standard split detection is only 64% efficient. We also show a displacement measurement beyond the quantum noise limit, using a squeezed vacuum TEM10 mode within the input beam. 
Vincent Delaubert (LKB - Jussieu, ACQAO), Nicolas Treps (LKB -   Jussieu), Mikael Lassen (DTU), Charles C. Harb (ACQAO), Cla...