Vol. 20, issue 01, article # 1

Nosov V. V. Reflectance of small-size optics. // Atmospheric and oceanic optics. 2007. V. 20. No. 01. P. 1-8.    PDF
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Abstract:

Formulas for reflection coefficient (reflectance) of widespread small-size optics (television, video and photo cameras, binoculars, etc.) are derived, in which the receiver plays a part of the reflector. A generalized Airy formula is derived taking into account the phase shifts due to the surface curvature. It is shown that the front (input) surface of the objective is the main contributor to reflection coefficient of the small-size optics. This surface is usually an air–crown interface with reflectance of approximately 4%. The reflection coefficient of such optics, in its shape, coincides with the typical initial condition for the Gaussian beam. It is shown that the plane wave, incident on the small-size optics, is reflected in the form of a spherical wave.