Information coding and retrieving using fluorescent semiconductor nanocrystals for object identification

The spectral features, i.e., wavelength and intensity, of fluorescence generated from semiconductor nanocrystals ( quantum dots) can be used for coding information. Unlike the 1-D and 2-D barcodes, the information carrier is applied to a very small area and hardly visible. The information retrieving by a fluorospectrometer is not subjected to the changes of rotation and scale. A de-convolution-based algorithm is used to separate the overlapped spectral profiles. This technology can be applied to small products labeling, document security and object identification. (C) 2004 Optical Society of America.