Security markers for determining composition of a medium
View Patent ↗A method of determining a component of a medium comprises illuminating the medium to excite a marker associated with the component. Detected photoluminescent emission from the marker in response to the excitation is compared with one or more emission profiles. The component is identified based on a match between the detected photoluminescent emission and at least one of the emission profiles.
1. A method of determining a component of a medium, the method comprising:
illuminating the medium to excite a marker associated with the component;
detecting photoluminescent emission from the marker in response to the excitation;
comparing the detected photoluminescent emission with one or more emission profiles associated with the marker;
identifying the component based on a match between the detected photoluminescent emission and at least one of the one or more emission profiles.
illuminating the medium to excite a marker associated with a second component of the medium;
detecting a second photoluminescent emission from the marker associated with the second component in response to the excitation;
comparing the detected second photoluminescent emission with one or more emission profiles associated with the second marker; and
identifying the second component based on a match between the detected second photoluminescent emission and at least one of the one or more emission profiles associated with the second marker.
2. The method of claim 1 , wherein illuminating the medium to excite a marker associated with the component comprises illuminating the medium at one or more absorption wavelengths associated with the marker.
3. The method of claim 1 , wherein detecting photoluminescent emission from the marker comprises detecting photoluminescent emissions from the marker at one or more emission wavelengths associated with the marker.
4. The method of claim 1 , wherein the one or more emission profiles associated with the marker comprise one or more photoluminescent signatures associated with the marker.
5. The method of claim 1 , wherein the marker comprises a carrier doped with one or more rare earth elements.
6. The method of claim 5 , wherein the carrier comprises a glass.
7. A method of analyzing a medium comprising a plurality of components to determine a concentration of at least one of the components, the method comprising:
illuminating the medium to excite one or more photoluminescent markers associated with each component of the medium;
detecting photoluminescent emission from the one or more photoluminescent markers associated with each component in response to the excitation;
generating a composite photoluminescent signature from the detected photoluminescent emission;
processing the composite photoluminescent signature to ascertain the contribution to the composite photoluminescent signature from a component; and
calculating the concentration of the component based on the processed composite photoluminescent signature and the ascertained contribution.
8. The method of claim 7 , wherein at least one of the one or more photoluminescent markers associated with each component of the medium is unique for each component.
9. The method of claim 7 , wherein at least one of the one or more photoluminescent markers associated with each component of the medium is the same for each component.
10. The method of claim 7 , wherein:
illuminating the medium comprises illuminating the medium at a first excitation wavelength and then illuminating the medium at a second excitation wavelength; and
detecting photoluminescent emission from the medium comprises detecting photoluminescent emission resulting from illumination at the first excitation wavelength, then detecting photoluminescent emission resulting from illumination at the second excitation wavelength.
11. The method of claim 7 , wherein calculating the concentration of the component comprises calculating a ratio of intensity of photoluminescent emission from the one or more photoluminescent markers associated with the component to a composite intensity of photoluminescent emission from the one or more photoluminescent markers associated with each component at one or more wavelengths.
12. The method of claim 7 , wherein the one or more photoluminescent markers each comprise a carrier doped with one or more rare earth elements.
13. The method of claim 12 , wherein the carrier comprises a glass.
14. A system for determining a concentration of a component of a medium, the system comprising:
a light source which illuminates the medium and excites one or more photoluminescent markers associated with each component of the medium;
a detector which detects photoluminescent emission from the one or more photoluminescent markers in response to the excitation;
a processor which generates a composite photoluminescent signature from the detected photoluminescent emission, processes the composite photoluminescent signature to ascertain a contribution from a component, and calculates the concentration of the component based on the processed composite photoluminescent signature and the ascertained contribution.
15. The system of claim 14 , wherein the one or more photoluminescent markers each comprise a carrier doped with one or more rare earth elements.
16. The system of claim 15 , wherein the carrier comprises a glass.