Basic Aplanatic Spherical Lens with Axial Linear Distribution of Refractive Index

• Main Author: T. S. Rovenskaya
• Format: Article
• Language: Russian
• Published: MGTU im. N.È. Baumana 2015-01-01
• Series: Nauka i Obrazovanie
• Subjects: aberration; aplanatic correction; gradient lens; the axial distribution of refractive index; aspherical lens
• Online Access: http://technomag.edu.ru/jour/article/view/883

<p>The use of gradient optical elements (GOE) from materials with a given spatial change of the refractive index (RI) in optical systems allows us to improve quality, increase reliability, and reduce weight and dimensions of the optical systems in electro-optic and laser devices.</p><p>The object of research is constructive and aberration properties of the GOE as the positive lens formed by spherical centered surfaces that restrict environment with a linear change of RI: n(z) = n0 + n1 * z; the axis OZ coincides with the geometrical optical axis of the lens, n1 is the coefficient.</p><p>In order to study the axial thickness (d = 10mm) and RI of the base n0 at a given focal length (f' = 100 mm), a parametric synthesis of the lens, located in the air, is performed using a developed technique to provide elimination of spherical aberration and coma of the third order for an infinitely remote object. Thus, designs were considered when the RI gradient was introduced at an axial thickness of lenses or at a depth of the pointer of its first surface in the light aperture, defined at a relative aperture of 1:2 and angular field in object space of 30°. The synthesis is performed when you change the RI of the base in the range from 1.5 to 1.9; this corresponds to an optical glass and plastic in the visible and near IR region of the spectrum.</p><p>The analysis was conducted regarding the form, monochromatic amounts of Seidel, and real aberrations with identification of higher-order aberrations, as well as depth values of the gradient layer t and the maximum change of RI - Δn. Values of t and Δn are related to process parameters determined by the method of manufacturing gradient material. The results characterize the family of basic aplanatic lenses that either can be used as the independent functional units (singleton collimators) or enter into the aperture component of a multicomponent optical system as its base lenses (lenses – monochromators, telephoto lenses, optical condensers). The GOE with an alternative solution in the form of basic RI homogeneous lens is compared with the first aspheric surface of the second order.</p>