Patent ID: 8233349

Claim:
A system for generating a beam of acoustic energy in a borehole, the system being configured and sized to be positionable within the borehole and comprising: a transducer configured and arranged to generate a first acoustic wave at a first frequency and a second acoustic wave at a second frequency; a non-linear material arranged to receive the first and second waves, wherein, in operation of the transducer, the first and second acoustic waves pass through the non-linear material, and a composition of the non-linear material produces a collimated beam by mixing of the first and second acoustic waves, such that the collimated beam has a frequency equal to a difference of the frequencies of the first and the second acoustic waves, and wherein the collimated beam has a frequency of at least 20 kHz; and a steering device arranged to direct the collimated beam away from the borehole into the material around the borehole.