Patent ID: 8227254

Claim:
A holographic element comprising: (i) a medium comprising a sensor polymer which incorporates a sensor group of the following formula: wherein: J is independently —CH 2 — or —CH 2 CH 2 —; n is independently 0, 1, 2, or 3; each R R is independently a ring substituent selected from C 1-6 alkoxy, —NO 2 , C 1-7 alkyl-acyl, C 5-10 aryl-acyl, C 5-10 aryl-C 1-7 alkyl-acyl, —OH, —COOH, —F, —Cl, —Br, —I, and —CN; and the ring attachment is via the 3-, 4-, 5-, or 6-ring position; and (ii) a hologram disposed within a part of the volume of the medium; wherein the hologram is: a “phase” hologram comprising a 3-dimensional distribution (modulation) of refractive index wherein the distribution is a physical record of an original interference pattern; and/or an “amplitude” hologram comprising a 3-dimensional distribution (modulation) of a radiation-absorbing material, wherein the distribution is a physical record of an original interference pattern.