The quantum laser pointer and other applications of squeezed light

摘要

The quantum nature of light imposes a limit to the detection of all properties of a laser beam. We show how we can reduce this limit for a measurement of the position of a light beam on a quadrant detector, simultaneously in two transverse directions. This quantum laser pointer can measure the beam direction with greater precision than a usual laser. We achieve this by combining three beams, one intense coherent and two vacuum squeezed beams, with minimum losses into one spatially multimode beam optimized for this application.