Abstract

The measurement of the Numerical Aperture (N.A.) of a distributed index (DI) planar microlens¹⁾ is important for its evaluation of focusing power. There have been some methods of measuring the N.A. of conventional lenses, e.g., the ratio of aperture diameter and focal length is easily determined and sometimes, the Apertmeter²⁾ has been utilized. The planar microlens, on the other hand, has some situations different from conventional spherical lens; i.e., the size of its diameter is smaller than 1 mm and the focal length is 1.5 mm~2 mm. Moreover, the physical edge of DI microlens does not necessarily indicate the effective lens size, if the index distribution near the periphery does not suitably contribute to focusing. We must, therefore, introduce some new method for measuring N.A. of planar microlens.

© 1984 Optical Society of America