Focusing Properties of an Acoustic Thin Lens and Zone Plate

摘要

A thin lens is defined as one that has thickness very small compared to theobject or image distances. There are several parameters, or degrees of freedom, that must be determined when designing a lens for a specific application. The radii of curvature of the surfaces, the types of materials to use and their indices of refraction, the diameter, the thickness desired, and the focal length that can be tolerated are all parameters that may be varied to obtain the desired lens performance. An additional requirement for this application is size and weight. It is always desirable to be as lightweight and as small as possible. The complete design must be as close to neutrally buoyant as possible. This puts some limitations on the materials that can be used.