A recent patent from US Navy reveals details of their awesome quantum photonic imaging device to detect of underwater objects. The patented invention would provide complete stealth during operation.
The invention uses quantum entanglement as a means to achieve detection of reflected radiation at levels that are below the noise level.
In a way, this is similar to how CDMA works by spreading information under the noise floor making it virtually indistinguishable from noise until it’s correlated with the correct code sequence. Just like that, the patented device generates a pair of entangled photons one of which (call it “probe photon”) is transmitted towards a target. The probe photon is reflected by the target. The reflected radiation which includes noise is then correlated with the other photon of the pair. Only when the reflected radiation includes a reflection of the probe photon, the correlation with the other photon is high, which indicates presence of an object. Multiple pairs of entangled photons are used to determine range and geometry of the target object.
The target object can be an Arctic ice canopy, ocean bottom, and another natural or artificial obstacle in the water that can obstruct under-ice passage of the vehicle in Arctic waters.
The patented device is particularly useful under Arctic sea-ice canopy, where conventional current underwater navigation systems fail.
Conventional arctic underwater vehicles use an (detection systems employ) active sonar array to avoid an accidental collision with the ice canopy. However, in the case of Arctic military operations, active sonar will give away the position of the submarine.