Abstract
The effect on PA image of the method of coupling the sample and detector was investigated experimentally. Three coupling methods, i. e. rigid coupling, coupling using liquids, and coupling using sheet materials, were tested in terms of signal intensity and image distortion. Highly viscous liquid proved to be nearly as good as the rigid combination in terms of signal intensity and distortion over the frequency range 200 Hz to 200 kHz. Taking separability into consideration, the use of viscous liquid under pressure is the most practical coupling method.
