Increase in performances of focused microacoustic sensors by couplant adjustment

The characteristics of the various modes of acoustic waves (velocity, atten uation, efficiency) radiated towards the focused sensor of an acoustic micr oscope are related to the acoustic properties of the coupling fluid. The aq ueous solutions of electrolytes are suitable as coupling fluids because the ir acoustic properties can be adjusted owing to the choice of the nature an d of the concentration of the dissolved ions. By adjusting the properties o f the couplant, the performances of the sensors of the acoustic microscopes can be extended. The image contrasts and the accuracy of measurements of t he acoustic waves velocity are improved, the radiation of the chosen modes are enhanced and very high frequencies can be used.