COVERT TAGGING OF AIRCRAFT FROM STANDOFF POSITIONS

TOPIC 91-CG17 STATES THAT LAW ENFORCEMENT AIRCRAFT SOMETIMESENCOUNTER SUSPICIOUS AIRCRAFT WHILE ALOFT. MEANS FOR "MARKING" OR "TAGGING" SUCH AIRCRAFT IN A COVERT AND HARMLESS MANNER FOR FUTURE LEGAL IDENTIFICATION IS REQUIRED. THE TAGGING MEANS PROPOSED HERE IS TO IRRADIATE A SMALL SPOTON THE PAINTED SURFACE OF THE SUSPECT AIRCRAFT WITH A PULSE OF RADIATION FROM AN ULTRA-VIOLET LASER SYSTEM MOUNTED ON THE LAW ENFORCEMENT AIRCRAFT. IF THE LASER FREQUENCY =NU, AND IF HNU<EB WHERE EB IS THE BOND ENERGY OF THE SURFACE PAINT-PIGMENT MOLECULES, THEN THOSE MOLECULES HAVE A HIGH PROBABILITY OF BEING DISSOCIATED INTO OTHER COMPOUNDS. THE SPATIALLY-CODED MARK (NUMBERS OR LETTERS), WOULD NOT BE VISIBLE TO THE EYE, OR DAMAGING TOTHE PAINT. IN PHASE I SAMPLES OF TYPICAL AIRCRAFT PAINT ON TEST SWATCHES WOULD BE IRRADIATED BY 2ND HARMONIC RADIATION FROM A DYE-LASER-KDP CRYSTAL SYSTEM. THE IRRADIATED SWATCHES WOULD THEN BE SUBJECTED TO A SERIES OF TESTS DESIGNED TO MAKE THE IRRADIATED SPOTS VISIBLE. SIX APPROACHES HAVE ALREADY BEEN SUGGESTED. MORE WILL BE IDENTIFIED IN PHASE I. IN ADDITION, AN OPTICAL DESIGN AND SYSTEM SPECIFICATION WOULD BE GENERATED PREPARATORY TO PHASE II EFFORTS.