Patent ID: 8039818

Claim:
A method of detecting a presence of a luminophore in a medium, the method comprising: providing excitation radiation to a detection volume formed in an aperture extending through a material, the detection volume being positioned at an exit of the aperture and defined, in part, by an aperture width corresponding to a smallest in plane dimension of the aperture; providing the luminophore in the medium in the detection volume, the luminophore being excitable by the excitation radiation to emit luminescent radiation; and detecting at least a polarization component of the luminescent radiation emitted through an exit of the aperture, wherein the luminophore is selected to emit luminescent radiation having a wavelength in the medium that is larger than twice the aperture width, and the luminophore is selected to be excitable by the excitation radiation having a wavelength in the medium that is smaller than twice the aperture width, and wherein the detection volume is further defined by the wavelength of the luminescent radiation, in that detection of luminescent radiation emitted by a luminophore not in the detection volume is suppressed by the aperture width.