Object identification using quantum dots fluorescence allocated on fraunhofer solar spectral lines

Abstract

An optical based identification system that is easily deployable and can be used in broad daylight. Fluorescent semiconductor nanocrystals (quantum dots) that fluoresce at specific wavelengths are distributed in a suitable polymer. The resulting mixture can then be applied as paint or on an adhesive label for application to a portion of any equipment or member of a friendly unit. The system also has a corresponding detectional processing unit which may be mounted on ordnance or on any other equipment such as aircraft. The detection unit uses a laser, which when active, causes a laser beam to strike the paint or adhesive able applied to the friendly unit. This causes the quantum dots to fluoresce. The fluorescence of the quantum dots can be detected by the sensor portion of the detection/processing unit. The sensor portion then transmits the data generated by the detected fluorescence to a data processing portion detection/processing unit such as a corresponding signal to the equipment operator or, if the unit is mounted on ordnance that has been launched to the warhead to deactivate the warhead. To overcome the effects of broad daylight on an optical system, the quantum dots can be detected by the sensor portions of the detection/processing unit. The sensor portion then transmits the data generated by the detected fluorescence to a data processing portion which decodes the data. If the decoded data indicates a friendly unit, the detection/processing unit sends a corresponding signal to the equipment operator or, if the unit is mounted on ordnance that has been launched to the warhead to deactivate the warhead. To overcome the effects of broad daylight on an optical system, the quantum dots are engineered to fluoresce at wavelengths corresponding to the absorption lines of the solar spectrum, more commonly known as Fraunhofer lines.

1 . An identification coating to be applied to a surface, said coating comprising:
 fluorescent semiconductor nanocrystals which fluoresce at specific wavelengths, at least one of said specific wavelengths corresponding to a wavelength of a Fraunhofer line in the sun's spectrum;   a polymer in which said nanocrystals are distributed.   
   
   
       2 . A coating according to  claim 1  wherein said coating is formed from a formulated system which includes a solvent. 
   
   
       3 . A coating according to  claim 1  wherein said coating is applied to a subject as paint. 
   
   
       4 . A coating according to  claim 1  wherein said coating has encoded thereon an identification code, said identification code being encoded using said specific wavelengths. 
   
   
       5 . A coating according to  claim 1  wherein said coating is applied as a layer in a multiple layer adhesive label.