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Journal of Nanomaterials
Volume 2008 (2008), Article ID 589532, 9 pages
Research Article

Advanced Secure Information Retrieval Technology for Multilayer Information Extraction

1Imaging Devices Group, Institute for Microstructural Sciences, National Research Council of Canada, Ottawa, ON, Canada K1A 0R6
2Molecular & Nanomaterials Architecture Group, Steacie Institute for Molecular Sciences, National Research Council Canada, Ottawa, ON, Canada K1A 0R6

Received 19 September 2008; Accepted 18 December 2008

Academic Editor: Jun Liu

Copyright © 2008 Shoude Chang et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Secure information retrieval technology aims at status identification and documentation authentication. Ideally, materials or devices used in these technologies should be hard to find, difficult to counterfeit, and as simple as possible. This manuscript addresses a novel information retrieval technology, with photoluminescent (PL) semiconductor quantum dots (QDs) synthesized via wet chemistry approaches used as its coding materials. Conceptually, these QDs are designed to exhibit emission at Fraunhofer line positions, namely, black lines in the solar spectrum; thus, the retrieval system can extract useful information under sunshine covering areas. Furthermore, multiphoton excitation (MPE) technology enables the retrieval system to be multilayer information extraction, with thin films consisting of QDs applied to various substrates, such as military helmets and vehicle and fingernails. Anticipated applications include security, military, and law enforcement. QD-based security information can be easily destroyed by preset expiration in the presence of timing agents.