Low numerical aperture exclusion imaging

A low numerical aperture exclusion imaging apparatus having an electromagnetic illumination source for illuminating a portion of a specimen on an object plane and an objective lens optically coupled to the electromagnetic illuminated portion of the specimen, for collecting an image created by the electromagnetic radiation illuminating the portion of the specimen, the image to be imaged on an image plane, the apparatus comprising;

• an optical plate, wherein the optical plate is positioned to block electromagnetic radiation transmitted through a center portion of the objective lens, and wherein the optical plate and the objective lens are symmetric about a common axis, wherein the optical plate comprises:
• an absorptive optical filter disposed substantially concentrically with the optical plate;
• and
• an optically transparent window around the absorptive optical filter, wherein the optically transparent window comprises a wavelength specific filter.

A low numerical aperture exclusion system having an objective lens and an imaging lens for imaging a particle, the system comprising:

• an optical plate disposed between the particle and the imaging lens and optically coupled to the particle;
• wherein the optical plate is positioned to block light transmitted through a center portion of the imaging lens, and wherein the optical plate and the imaging lens are symmetric about a common axis;
• and
• wherein the optical plate comprises:
• an optically transparent window, wherein the optically transparent window comprises:
• an optical filter disposed substantially concentrically with the optically transparent window;
• and
• a wavelength specific filter.