Sensing method including interrogation of a holographic sensor
View Patent ↗A sensing method, which comprises subjecting a holographic sensor to an external physical interaction to which the sensor is sensitive, and observing a change in the holographic image.
1. A sensing method, which comprises:
subjecting a holographic sensor to an external physical interaction, wherein the sensor is a volume hologram recorded in a support medium that is directly sensitive to the external physical interaction, wherein the volume hologram produces a holographic image; and
observing a change in the holographic image;
wherein the external physical interaction is temperature, and wherein the change in the holographic image is a change of color or a change of image to show that the volume hologram is genuine;
wherein the support medium is a polymer that is highly sensitive to changes in temperature such that the polymer has a rigid structure which collapses upon an increase in temperature, thereby producing a significant shift in a wavelength of reflection of the polymer; and
wherein the volume hologram comprises a reflection hologram.
2. The method according to claim 1 , wherein the support medium comprises a polymer.
3. The method according to claim 1 , wherein the change in the holographic image is reversible.
4. The method according to claim 3 , wherein the change in the holographic image is a change of color or a change of image to show that the volume hologram is genuine for the purpose of authentication.
5. The method according to claim 1 , wherein the volume hologram is viewable under white light, UV light or infra-red radiation.
6. The method according to claim 1 , wherein the change in the holographic image is a change of color or a change of image to show that the volume hologram is genuine for the purpose of authentication.
7. The method according to claim 1 , wherein the polymer is poly(N-isopropylacrylamide).
8. A sensing method, which comprises:
subjecting a holographic sensor to an external physical interaction, wherein the sensor is a volume hologram recorded in a support medium that is directly sensitive to the external physical interaction, wherein the volume hologram produces a holographic image; and
observing a change in the holographic image;
wherein the external physical interaction is magnetism, and wherein the change in the holographic image is a change of color or a change of image to show that the volume hologram is genuine;
wherein the support medium is magnetic; and
wherein the volume hologram comprises a reflection hologram.
9. The method according to claim 8 , wherein the support medium comprises a polymer.
10. The method according to claim 8 , wherein the change in the holographic image is reversible.
11. The method according to claim 8 , wherein the volume hologram is viewable under white light, UV light or infra-red radiation.
12. The method according to claim 8 , wherein the change in the holographic image is a change of color or a change of image to show that the volume hologram is genuine for the purpose of authentication.
13. The method according to claim 10 , wherein the change in the holographic image is a change of color or a change of image to show that the volume hologram is genuine for the purpose of authentication.
14. The method according to claim 8 , wherein the support medium comprises a molecular magnet.
15. The method according to claim 8 , wherein the support medium comprises a ferro-magnetic polymer.
16. The method according to claim 8 , wherein the support medium comprises a ferri-magnetic polymer.
17. The method according to claim 8 , wherein the support medium is a copolymer of aniline and tetracyanoquinoline.