Entangled photon identification system and method for quantum optical measurement

A method for imaging using entangled photons, the method comprising:

• a) generating a set of four entangled photons that are correlated in time, such that any one pair of the four entangled photons being correlated in time indicates that all four of the entangled photons are entangled;
• b) directing a first photon of the set of four entangled photons along a first path;
• c) directing a second photon of the set of four entangled photons along a second path;
• d) directing a third photon of the set of four entangled photons along a third path;
• e) directing a fourth photon of the set of four entangled photons along a fourth path;
• f) illuminating an object positioned in an object plane in the first path with the first photon of the set of four entangled photons, thereby modulating the first photon of the set of four entangled photons;
• g) detecting the modulated first photon of the set of four entangled photons;
• h) spatially sampling the second photon of the set of four entangled photons in the second path;
• i) detecting the third photon of the set of four entangled photons in the third path;
• j) detecting the fourth photon of the set of four entangled photons in the fourth path;
• k) determining a coincidence between a detection of the modulated first photon of the set of four entangled photons and a detection of the third photon of the set of four entangled photons;
• l) Determining a coincidence between a spatial sample of the second photon of the set of four entangled photons and a detection of the fourth photon of the set of four entangled photons;
• and
• m) generating an image of the object positioned in the object plane using the determined coincidences.

A method of imaging, the method comprising:

• a) generating a set of four entangled photons including a first, a second, a third, and a fourth entangled photons that are correlated in time, such that detection of any one pair of the four entangled photons indicates that all four of the entangled photons are entangled;
• b) coupling the first entangled photon to a first path, the second entangled photon to a second path, the third entangled photon to a third path, and the fourth entangled photon to a fourth path;
• c) generating a modulation of the first photon from an object positioned at an object plane;
• d) detecting the modulated first entangled photon;
• e) detecting the second entangled photon with a spatial sampler;
• f) detecting the third entangled photon;
• g) detecting the fourth entangled photon;
• h) determining a coincidence between a detection of the modulated first entangled photon and a detection of the third entangled photon;
• i) determining a coincidence between a spatial sample of the second entangled photon and the detection of the fourth entangled photon;
• and
• j) generating an image of the object using the coincidences determined by the first and second coincidences.