We report, for the first time to our knowledge, fabrication of two types of negative-index-change waveguide lens in LiNbO3 by using ion milling. The first type is an analog Fresnel lens formed by grooves milled into the waveguide. The second is a hybrid lens that combines analog Fresnel zones in the central region with chirp gratings on the sides formed by the same means. We have obtained simultaneously high-efficiency and near-diffraction-limited focusing characteristics in both types of lens. The ion-milling technique employed should be capable of producing similar lenses in any other waveguide substrate, such as GaAs.
© 1988 Optical Society of America
Original Manuscript: June 21, 1988
Manuscript Accepted: September 15, 1988
Published: December 1, 1988
T. Q. Vu, J. A. Norris, and C. S. Tsai, "Formation of negative-index-change waveguide lenses in LiNbO3 by using ion milling," Opt. Lett. 13, 1141-1143 (1988)