Abstract: The waveguide comprises a transparent body having a very sharp point at one end and being coated with a first opaque layer, such as metal. The first opaque layer carries a layer of an optically transparent material which is covered, in turn, by a second opaque layer. The apex of the point has been removed so as to expose the transparent body through a first aperture and to expose the transparent layer through a second aperture, the first aperture occupying an area of less than 0.01 .mu.m.sup.2.Light enters the transparent body at its remote end and exits through the first aperture to illuminate an object. Reflected light from the object enters the transparent layer through the second aperture and is guided to a light detector for further processing.

Abstract: The disclosed scanning acoustic microscope comprises a solid lens body consisting of two sections of materials having different sound propagation characteristics but matching acoustic impedances. A lens is formed by the interface of said two sections and has a focal point coinciding with the apex of a sharply pointed tip formed at the free surface of one of said sections. The tip and the specimen to be investigated are immersed in a coupling medium having a relatively high acoustic absorption coefficient. The lens body carries an acoustic transducer on its surface remote from the tip for sending plane sound waves through the lens and tip onto the specimen. Acoustic waves reflected from the specimen are also received by this transducer. Acoustic waves transmitted through the specimen optionally may be received by a transducer arranged on the opposite side of the specimen. By appropriate processing of the received signals, high-resolution (10 nm) images of the specimen can be obtained.