With refraction microscope optics it is generally understood that as magnification increases field-of-view will decrease. This constraint has posed scaling limitations for microscopy of large objects. We have shown in theory and proven in a reduction-to-practice that in the special case of grazing incidence diffraction, as magnification increases, field-of-view remains constant while efficiency goes down. This distinction has utility for many 3D optical inspection tasks. A holographic optical element (HOE) is used as the microscope's primary objective, and a laser stripe is used to interrogate target surfaces. The microscope's HOE can be embossed in polycarbonate and offered as a consumable part that can be replaced inexpensively if it becomes contaminated. Specimens can be placed on a moveable stage and advanced to collect a sequence of 3D profiles. Laser speckle is ameliorated as a natural consequence of the scanning mechanism. A prototype of the microscope has been demonstrated in a desktop embodiment. It is contemplated as a profiler for industrial inspection and quality control.

Date Published: 10 September 2009
PDF: 8 pages
Proc. SPIE 7432, Optical Inspection and Metrology for Non-Optics Industries, 74320V (10 September 2009); doi: 10.1117/12.826574

Published in SPIE Proceedings Vol. 7432:
Optical Inspection and Metrology for Non-Optics Industries
Peisen S. Huang; Toru Yoshizawa; Kevin G. Harding, Editor(s)