REFLECTANCE OF SMALL-SIZE OPTICS

摘要

Expressions for reflection coefficient (reflectance) of commonly used small-size optics (TV cameras, video cameras, cameras, binoculars etc.), when a receiver acts as a reflector, have been obtained. A generalized Airy formula taking into account phase incursion owing to surfaces curvature has been determined. It is shown that primary contribution into small-size optics reflectance is made by an objective front (entrance) surface. This surface is usually an air-crownglass boundary with a reflectance of about 4%. The reflection coefficient of such optics coincides in shape with a typical initial condition for Gaussian beam. It is shown that a plane wave falling on the small-size optics reflects in the form of spherical wave.