The Preparation of Macro Axial Gradient Index Glasses for F/3 Singlet Lenses

Abstract

Macro-size axial gradient index glasses with different refractive index profiles have been produced by fusing together layers of glasses of progressively different indices of refraction. Smooth, step-free gradients are formed by controlled diffusion within and across the layers. The refractive index profiles and wavefront distortions of the lens blanks made from these materials were characterized. Different F/3 singlet lenses were designed and fabricated using these gradient glasses. The performance of these gradient lenses were tested using MTF and interferogram methods. These lenses, having only spherical surfaces, have practically no spherical aberration, and the on-axis performance reached diffraction limit. The methods of preparation of the gradient materials are discussed as well as the advantageous properties of macro gradients in optics.