Making fast cylindrical gradient-index lenses diffraction limited by using a wave-front-correction element

摘要

A wave-front-correction element (WFCE) is produced to make a cylindrical Ag-ion-exchanged gradient index (GRIN) lens with a high numerical aperture (0.53) diffraction limited (wave-front error, 0.02 lambda rms). The Nave-front aberrations of the cylindrical GRIN lens are measured by a phase-shifting shearing interferometer, with a conventional microscope objective used as a compensation lens. The continuous surface relief of the WFCE is produced by a lithographic process. The wavefront-corrected GRIN lens is applied to collimate the strongly divergent light (57 degrees full diverging angle measured at 1/e(2) of maximum intensity) emitted by a high-power diode laser. The power irradiated into a full angle of 2 mrad can be enhanced by a factor of 1.8 with the WFCE. (C) 1998 Optical Society of America. [References: 10]