Patent ID: 6909497
Filing Date: 2005-06-21
Classification: G01M

Abstract:
1. A quantum optical measurement apparatus for determining an optical characteristic of an optical element comprising: an entangled photon source in optical communication with the optical element to be measured, said entangled photon source generating a plurality of photon pairs (twinons), each of said twinons comprising a first twin photon and a second twin photon, said first twin photon being correlated to said second twin photon in at least one of time, wavelength and polarization; a first beamsplitter element in optical communication with said optical element to be measured, said beamsplitter element providing a first optical path and a second optical path for said twinons; a second beamsplitter element, along said first optical path, in optical communication with said first beamsplitter element, said second beamsplitter element providing a first optical branch and a second optical branch for said twinons; a variable optical delay element simultaneously in optical communication with both the first and second optical branches, wherein there is an additional predetermined fixed delay between the first and second optical branches, wherein also said variable optical delay element is controlled by an external signal; a plurality of first detectors in optical communication with said second beamsplitter element, each of said first detectors adapted to receive photons in one of said optical branches; and a second detector in optical communication with said first beamsplitter element along said second optical path, wherein each of said plurality of first detectors and said second detector is preceded by an optical polarizer, each of said polarizers being oriented at 45 degrees to the polarization axes of said twinons.