Abstract

The oblique viewing microscope is an optical instrument comprised of three parts. The first part is a relay lens which is a unity magnification system, preferably telecentric. The second part is a planar diffraction grating. The third part is a small to moderate numerical aperture microscope. With the appropriate geometric configuration, monochromatic illumination and suitable grating choice, microscopic observation at enormous oblique angles (e.g., 50°) becomes possible without defocusing or distortion problems whatsoever. The imaging process in this instrument is described, particularly the rendition of 3-D objects as well as the function of the grating, which is used here as a genuine imaging component. With the proper choice of pupil location the resolution is completely isotropic. Defocusing in this instrument is a little more complicated than in the conventional case as an astigmatic term appears. The defocusing tolerances are given.

© 1988 Optical Society of America