FOCUSING THROUGH AN INTERFACE - SCANNING AND LOCALIZING THE INTENSITY

Focusing light through an interface leads to an aberrated intensity di stribution that is highly extended with a relatively low peak intensit y. We present a method, using a well-chosen annular aperture, that can greatly improve the localization of the intensity about a prescribed point on the axis. Also, the intensity at that point can be increased significantly. By continuously varying the annulus radii, we can scan the intensity peak through the second medium. This localization and sc anning method has possible applications in three-dimensional imaging a nd lithography. (C) 1998 Optical Society of America.