PHASE APODIZATION OF LENSES TO INCREASE THE FOCAL DEPTH
I.G. Palchikova, E.S. Smirnov
Technological Design Institute of Scientific Instrument Engineering, Siberian Branch, Russian Academy of Sciences, Novosibirsk, Russia
Keywords: depth of field, a transmission function, modified lens, aberrations
Abstract
The paper substantiates a generalized method for calculating the phase transmission functions of modified lenses with increased depth of focus. An approach is proposed that uses not only the ray equation, but also a method for specifying a condition that determines the redistribution of energy from certain zones of the optical element to certain areas of the caustic. This allows you to specifically select the type of aberrations introduced. For three types of radiant energy flux power gradients, the types of aberrations introduced using aspherics were determined, and the phase transmission functions of the modified lenses were found. In the Kirchhoff-Fresnel scalar approximation, the intensity distribution in caustics is calculated. The intensity distributions along the optical axis of the focal segments of the modified lenses show significant fluctuations relative to the average values. The average values vary along the optical axis and have a magnitude of about 10-2 of the intensity at the focus of an ideal lens. The sizes of axisymmetric scattering circles in different sections of the focal segment also vary significantly relative to the Airy circle of the lens.
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