An optical device for sensing a presence of an analyte in a person is provided. The optical device includes a light source, an optical stack, and a reader. The light source emits a first light having a first wavelength. The optical stack is placed on a skin of the person. The optical stack includes a sensor material and an optical filter. The sensor material emits a second light having a second wavelength when irradiated with the first light. An optical property of the second light is sensitive to the presence of the analyte. The optical filter is disposed on the sensor material and includes a plurality of microlayers numbering at least 10 in total. The optical filter has different first and second transmittances at the respective first and second wavelengths.