Raman-active taggants and their recognition
AssigneeQuantag Systems, Inc.
InventorsAlexander Nikitovich Shchegolikhin, Olga Leonidovna Lazareva, Valery Pavlovich Mel'nikov, Vassili Yu Ozeretski, Lyle David Small
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Abstract
An organic or organoelement, linear or branched, monomeric or polymeric composition of matter having a Raman-active component in the form of particles. The particles having a maximum dimension of 50 μm. The Raman-active compound is applied to a substrate. When the Raman-active compound is exposed to a laser light wavelength which is batochromically well beyond a spectral region of maximum absorbance of said Raman-active compound, Raman scattering can be detected.
Claims21
A method of security marking, comprising the steps of:
- a) applying a Raman-active composition, comprising a conjugated polymer to a genuine item;
- b) illuminating the Raman-active composition with a near infrared light;
- c) measuring quantitatively an emissive spectrum of the Raman-active composition.
A method of security marking, comprising the steps of:
- a) applying to a genuine item a marking comprising a Raman-active composition, wherein the Raman-active composition includes a conjugated polymer when illuminated with a monochromatic near infrared light, generates a detectable Raman spectrum, thereby forming a machine-readable security mark on the genuine item;
- b) illuminating the machine-readable security mark on the genuine item with the monochromatic near infrared light;
- and
- c) quantitatively measuring with a spectrometer a Raman scattered light from the Raman-active composition while the machine-readable security mark is illuminated with the monochromatic near infrared light.
A method of security marking, comprising the steps of:
- a) applying to a genuine item a marking comprising a fluorescence-active composition, wherein the fluorescence-active composition, when illuminated with a monochromatic near infrared light, generates a detectable emission spectrum, thereby forming a machine-readable security mark on the genuine item;
- b) illuminating the machine-readable security mark on the genuine item with the monochromatic near infrared light;
- and
- c) simultaneously and quantitatively measuring with a spectrometer a composite emission spectrum of a Raman scattered light and of a laser induced fluorescence from the fluorescence-active composition while the machine-readable security mark is illuminated with the monochromatic near infrared light, wherein the fluorescence-active composition is essentially an inorganic anti-Stokes up-converting phosphor.
Dependencies are inferred from the claim text.