In one embodiment, a countermeasure system for protecting an asset from a missile attack includes a decoy comprising a plurality of quantum dots selected to emit radiation having a radiation emission profile similar to a profile of a radiation signature of the asset. In another embodiment, a method of simulating a radiation signature of an asset using quantum dots includes dispersing quantum dots to form a cloud of quantum dots; and exciting the quantum dots with a first radiation so that the quantum dots emit a second radiation having a profile similar to the radiation signature profile of the asset.