Resolution analysis of a gradient-index rod and a gradient-index lens array

The physical Optics analysis of a gradient-index (GRIN) rod and a GRIN lens array with aberrations is presented. We investigated the optical path length and aberration of a GRIN rod without definition of the stop plane. We also defined an effective aberration transmission function to include aberrations into physical optics analysis. Our theoretical results of impulse responses agree excellently with experiments. For a single GRIN rod, we obtained a theoretical value of 10.3 mu m and an experimental value of 10.4 mu m for the full width at half-maximum of the intensity point-spread function. For a GRIN array, the theoretical value of 19.2 mu m and the experimental measurement of 19.9 mu m agree to within 4%. This physical optics methodology with aberrations included can be applied to optical design software. The resolution difference in xerographic process for test material along the "parallel-to-perpendicular" directions is observed. It agrees with the theoretical result for the intensity impulse response of the GRIN array calculated with a second-order correction. (c) 2008 Optical Society of America