Patent ID: 7318907

Claim:
Apparatus for analyzing at least one small object comprising, a source of electromagnetic radiation, a radiation detector, a substantially planar light barrier interposed between said source and said radiation detector, said light barrier including a first electrically conductive surface on which the electromagnetic radiation from said source is incident, and at least one aperture through said light barrier, said aperture having a width in at least one dimension that is smaller than one wavelength of said electromagnetic radiation, at least some of said electromagnetic radiation passing from said source through said aperture to said radiation detector, wherein: a presence of said at least one small object in close proximity to said first electrically conductive surface causes a change in a resonance condition of said light barrier; said change in the resonance condition of said light barrier causes variations in said electromagnetic radiation; and said radiation detector is positioned with respect to the light barrier to receive said electromagnetic radiation exiting from the light barrier without significant alterations to said variations, so as to detect said variations in said electromagnetic radiation resulting from the change in the resonance condition of said light barrier due to the presence of said at least one small object in close proximity to said first electrically conductive surface.