Researchers from the University of Rochester in New York have demonstrated an aircraft detection system that is unjammable.
By using polarized photons to detect and image objects, any attempt to modify the photons will alter its quantum properties. The system can then detect the altered quantum state of the photons.
[thumb]http://www.technologyreview.com/view/508826/quantum-imaging-technique-heralds-unjammable-aircraft-detection/[/thumb]