Aberration distortions of a spherical geodesic waveguide lens in LiNbO3:Ti

Aberration distortions were determined at the focus of a spherical geodesic lens made from a waveguide formed by the diffusion of Ti in a Y-cut LiNbO₃ crystal. The experimental results were compared with calculations carried out in the geometric-optics and diffraction approximations. For a lens with a focal length f = 8.6 mm and a relative aperture of the incident beam amounting to 0.67, the size of the spot at the focus was ~4 μ when the relative amplitude of the side lobes was 9dB.