AN OPTICAL DEVICE AND A METHOD OF UTILIZING SUCH DEVICE FOR OPTICALLY EXAMINING OBJECTS

摘要

An optical device and a method of utilizing such device, based on the idea of interferometry, for optically examining objects where the optical device comprises a pair of diffraction graftings (G1, G2) with each of the graftings designed to reduce substantially all the diffraction orders except the +1 and -1 diffraction orders by the evanescent wave phenomenon and zero order cancellation.