Patent ID: 8871148

Claim:
A optically interrogatable sensing element for sensing an organic vapor analyte, comprising: an optically responsive layer between a reflective layer and a semi-reflective layer, wherein the optically responsive layer comprises at least a first, highly analyte-responsive sublayer and a second, minimally analyte-responsive sublayer; wherein the second, minimally analyte-responsive sublayer is optically compatible with the first, highly analyte-responsive sublayer, wherein the second, minimally analyte-responsive sublayer and the first, highly analyte-responsive sublayer are in overlapping relation with each other and exhibit identically shaped and sized borders, and wherein the ratio of the thickness of the first, highly analyte-responsive sublayer to that of the second, minimally analyte-responsive sublayer is from about 1:5 to about 1:1; and wherein the sensing element does not exhibit wraparound upon exposure to an atmosphere containing 1000 ppm of an organic vapor analyte.